TW202405097A - Silicone-releasant polyester film and production method therefor - Google Patents

Abstract

Provided are: a silicone-releasant polyester film that exhibits appropriate easy releasability and is suitable for use as, for example, a carrier film in producing multilayer ceramic capacitors and which enables even extremely thin films to be peeled off without breaking or being otherwise damaged; and a method for producing the silicone-releasant polyester film. The silicone-releasant polyester film includes a coating layer formed from a release coating composition comprising: an aqueous dispersion (1) of a silicone (A) having a number-average molecular weight of 25,000 or higher and having three or more alkenyl groups in the molecule; an aqueous dispersion (2) of a silicone (B) having a number-average molecular weight of 25,000 or less and having alkenyl groups in the molecule only at both ends thereof; an aqueous dispersion (3) of a silicone (C) having a number-average molecular weight of 10,000 or less and having a directly Si-atom-bonded hydrogen atom represented by Si-H group; and a platinum-based catalyst. When the total solid content of the silicone (A), silicone (B), and silicone (C) is taken as 100 parts by mass, the release coating composition contains 80 parts by mass or more of the silicone (A), 2-20 parts by mass of the silicone (B), and 2-20 parts by mass of the silicone (C).

Description

Polysilicone release polyester film and manufacturing method thereof

The invention relates to a polysilicone release polyester film. More specifically, the invention relates to a silicone release polyester film and a manufacturing method thereof. The silicone release polyester film is, for example, a ceramic green sheet used in the manufacture of multilayer ceramic capacitors. ) molding, etc., it has peelability and adhesion suitable for molding from light peeling to heavy peeling, and can prevent the occurrence of cracks and deformation of the green sheet (sheet), etc.

In the production of laminated ceramic capacitors, a release film is used as a carrier film for molding ceramic green sheets. Especially from the viewpoint of dimensional stability and heat resistance, polyester film is used as the base material of the release film. In recent years, multilayer ceramic capacitors have been miniaturized and increased in capacity. On the other hand, high reliability for automotive applications has become a must, and the demand for quality improvement of ceramic green sheets continues to rise.

As ceramic green sheets become thinner and more reliable, the thickness of the green sheets after drying is in the range of several μm or less. Therefore, the carrier film is particularly required to have light peelability. Due to thinning, the rigidity of the ceramic green sheet becomes lower. With the peeling force of conventional release films, cracks and deformation occur when the green sheet is peeled off, and the defective rate of the substrate (chip) worsens. Therefore, light peelability is required.

Therefore, there is a demand for reducing the peeling force of the release film. For example, a method of adjusting the peeling force by controlling the cross-linked structure of polysiloxane has been proposed (for example, Patent Document 1). However, this method of controlling the cross-linked structure of the release layer requires new designs such as polymers or cross-linking agents with special structures. Ultraviolet irradiation, electron beam irradiation, etc. require more powerful energy, so the cost becomes higher. problem.

In addition, a release layer composed of a silicone resin with a cross-linked structure and a silicone resin without a cross-linked structure has been proposed (for example, Patent Document 2). However, in this method, since the solvent of the coating agent used to form the release layer is an organic solvent, the organic solvent treatment equipment during coating or drying becomes large-scale, and it is also necessary to spend money to volatilize the organic solvent. There is a problem that the running cost of the process becomes high as a result.

Furthermore, there are problems with the working environment and safety problems such as fires caused by organic solvents. In addition, a method that does not use an organic solvent has also been proposed (for example, Patent Document 3). However, in this method, the viscosity of the coating agent increases, so the handling becomes complicated and there is a problem that it is difficult to apply uniformly. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2006-7689. [Patent Document 2] Japanese Patent Application Publication No. 2008-254207. [Patent Document 3] Japanese Patent Application Publication No. 2003-192987.

[Problem to be solved by the invention] In view of the above situation, the present invention aims, for example, to provide a silicone release-type polyester film, a method for manufacturing the same, and the like. The silicone-type release-type polyester film can be suitably used as a carrier in the production of laminated ceramic capacitors. Even if it is a very thin film, it can be peeled off without causing damage such as cracking, and has excellent light peeling properties. [Means used to solve problems]

The inventor of the present invention has devoted himself to research in order to solve the aforementioned problems, and found that by using a specific polydimethyl silicone to maximize the cross-linking density during the formation of the release layer, the problem can be solved. By solving the aforementioned problems, the present invention has been completed.

That is, the present invention provides the following silicone releaseable polyester film (polysilicone releaseable polyester film).

[1] A polysilicone release polyester film having a coating layer formed using a release coating composition containing: an aqueous dispersion of polysilicone (A) (1), the number average molecular weight of the aforementioned polysilicone (A) is 25,000 or more, and contains more than 3 alkenyl groups in one molecule; the aqueous dispersion (2) of the polysilicone (B), the aforementioned polysilicone (B) has a number average molecular weight of 25,000 or less, and has alkenyl groups only at both terminals in one molecule; the aqueous dispersion (3) of polysilicone (C), the number average molecular weight of the aforementioned polysilicone (C) is 10,000 or less, and having a hydrogen atom directly bonded to a Si atom represented by a Si-H group; and a platinum-based catalyst; after combining the aforementioned polysiloxane (A), the aforementioned polysiloxane (B) and the aforementioned polysiloxane When the total solid content of oxygen (C) is 100 parts by mass, it includes 80 parts by mass or more of the aforementioned polysiloxane (A) and 2 or more parts by mass and 20 parts by mass or less of the aforementioned polysiloxane (B). and 2 parts by mass or more and 20 parts by mass or less of the aforementioned polysiloxane (C).

[2] The polysilicone release polyester film according to the item [1], wherein the polysilicone (A) has alkenyl groups at both terminals and side chains of one molecule.

[3] The polysilicone release polyester film according to item [1] or [2], wherein the alkenyl group of the polysilicone (A) is a vinyl group.

[4] The polysilicone release polyester film according to any one of items [1] to [3], wherein the alkenyl group of the polysiloxy (B) is a vinyl group.

[5] The polysilicone release polyester film according to any one of items [1] to [4], wherein the polysilicone (A) and the polysilicone (B) are alkenyl-based ethylene films. base.

[6] The polysilicone release polyester film according to any one of items [1] to [5], wherein relative to the total amount of the polysilicone (A) and the polysilicone (B) , the content of the aforementioned platinum-based catalyst is 120 ppm or more.

[7] The polysilicone release polyester film described in any one of items [1] to [6] is used for molding ceramic green sheets in the manufacture of laminated ceramic capacitors.

In addition, the present invention provides the following method for manufacturing a polysilicone release polyester film.

[8] A method for manufacturing a polysilicone release polyester film, which includes the step of forming a coating layer using a release coating composition. The release coating composition includes: polysiloxane (A) The aqueous dispersion (1) of the polysilicone (A) has a number average molecular weight of 25,000 or more and contains more than 3 alkenyl groups in one molecule; the aqueous dispersion (2) of the polysilicone (B), The number average molecular weight of the aforementioned polysilicone (B) is 25,000 or less, and only has alkenyl groups at both terminals in one molecule; the aqueous dispersion (3) of the aforementioned polysilicone (C), The number average molecular weight is 10,000 or less, and has hydrogen atoms directly bonded to Si atoms represented by Si-H groups; and a platinum-based catalyst; in which the aforementioned polysiloxane (A) and the aforementioned polysiloxane (B) When the total solid content of the polysiloxane (C) is 100 parts by mass, it contains 80 parts by mass or more of the polysiloxane (A) and 2 parts by mass or more and 20 parts by mass or less of the polysiloxane. Oxygen (B) and 2 parts by mass or more and 20 parts by mass or less of the aforementioned polysiloxane (C).

[9] The method for producing a polysilicone release polyester film according to the item [8], wherein the polysilicone (A) has alkenyl groups at both ends and side chains of one molecule.

[10] The method for producing a polysilicone release polyester film as described in item [8] or [9], wherein the alkenyl group of the polysilicone (A) and the polysilicone (B) is vinyl. . [Invention effect]

By having the above-mentioned structure, the polysilicone release polyester film of the present invention can provide a release layer that can be peeled off without damage such as cracking even if it is a very thin film and has a moderately low peel strength. A release polyester film with excellent uniformity is used as a release film for green sheet forming. The release polyester film of the present invention having such characteristics can be suitably used as a carrier film for molding ceramic green sheets used in multilayer ceramic capacitors.

In addition, the method for manufacturing a silicone release polyester film of the present invention can efficiently and simply obtain a silicone release polyester film having the aforementioned characteristics.

Embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments.

＜Polysilicone release polyester film＞ The polysilicone release polyester film of the present invention has a coating layer formed using a release coating composition containing: an aqueous dispersion (1) of polysilicone (A) , the number average molecular weight of the aforementioned polysilicone (A) is 25,000 or more, and contains more than 3 alkenyl groups in one molecule; the aqueous dispersion (2) of the polysilicone (B), the aforementioned polysilicone (B) The number average molecular weight of the polysiloxane (C) is 25,000 or less, and only has alkenyl groups at both ends of one molecule; the aqueous dispersion (3) of polysiloxane (C), the number average molecular weight of the polysiloxane (C) is 10,000 or less, And it has a hydrogen atom directly bonded to a Si atom represented by a Si-H group; and a platinum-based catalyst; in which the aforementioned polysiloxane (A), the aforementioned polysiloxane (B) and the aforementioned polysiloxane (C) ) is 100 parts by mass, including 80 parts by mass or more of the aforementioned polysiloxane (A), 2 parts by mass or more and 20 parts by mass or less of the aforementioned polysiloxane (B) and 2 parts by mass parts or more to 20 parts by mass or less of the aforementioned polysiloxane (C).

[polyester film] As the polyester film of the present invention, known polyesters can be suitably used. For example, the polyesters shown below can be suitably used.

(polyester) In the present invention, the polyester constituting the polyester film used as the base film (hereinafter sometimes referred to as the “base material”) is not particularly limited. Generally, generally used polyesters that are film-molded can be used as the release film. Use base material. Preferably, it is a crystalline linear saturated polyester composed of an aromatic dibasic acid component and a glycol component, such as polyethylene terephthalate, polyethylene isophthalate, poly-2,6 -Ethylene naphthalate, polybutylene terephthalate, poly(1,4-cyclohexylenedimethylene terephthalate), poly(terephthalate) Trinylene dicarboxylate or a copolymer containing the constituent components of these resins as the main component is more suitable. Among them, a polyester film system formed of polyethylene terephthalate is particularly suitable. The repeating units of ethylene terephthalate in polyethylene terephthalate are preferably at least 90 mol%, more preferably at least 95 mol%. Other dicarboxylic acid components and glycol components may also be copolymerized in small amounts. For example, from a cost point of view, it is preferable to produce only terephthalic acid and ethylene glycol.

In addition, well-known additives such as antioxidants, light stabilizers, ultraviolet absorbers, crystallizers, etc. may also be added within the scope that does not hinder the efficacy of the release film of the present invention. From the perspective of high bidirectional elastic modulus and other reasons, the polyester film is preferably a biaxially oriented polyester film.

The intrinsic viscosity of the polyester film is preferably from 0.50 dl/g to 0.70 dl/g, more preferably from 0.52 dl/g to 0.65 dl/g. An intrinsic viscosity of 0.50 dl/g or more is preferable because cracking does not often occur during the stretching step. On the contrary, when the intrinsic viscosity is 0.70 dl/g or less, it is preferable because the cutability when cut into a predetermined finished product width is good and dimensional defects do not occur. In addition, it is preferable that the raw material particles be sufficiently vacuum dried.

In addition, in this specification, when only describing as "polyester film", it means the polyester film which has (laminated|stacked) the surface layer A and the surface layer B.

The method for producing the polyester film of the present invention is not particularly limited, and conventionally generally used methods can be used. For example, the polyester can be melted in an extruder, extruded into a film shape, cooled in a rotating cooling drum to obtain an unstretched film, and the polyester film can be obtained by biaxially stretching the unstretched film. The biaxially stretched film can be obtained by gradually biaxially stretching a longitudinally or transversely uniaxially stretched film in the transverse or longitudinal direction, or by simultaneously biaxially stretching an unstretched film in the longitudinal and transverse directions.

In the present invention, the stretching temperature when the polyester film is stretched is preferably equal to or higher than the secondary transition point (Tg) of polyester. The extension can be carried out in the longitudinal and transverse directions from 1 time to 8 times, preferably from 2 times to 6 times.

The thickness of the polyester film is preferably from 12 μm to 100 μm, more preferably from 16 μm to 50 μm, further preferably from 19 μm to 33 μm. As long as the thickness of the film is 12 μm or more, it is preferable because there is no risk of thermal deformation during film production, processing steps, or molding. On the other hand, as long as the thickness of the film is 100 μm or less, the amount of film discarded after use will not increase extremely, which is preferable in terms of reducing environmental load.

The aforementioned polyester film base material may be a single layer, or multiple layers of two or more layers may be used. For example, the base film may be a polyester film having a surface layer A that does not substantially contain particles having a particle diameter of 1.0 μm or more, and a surface layer B that contains particles. It is preferred that the surface layer A substantially contains no inorganic particles having a particle size of 1.0 μm or more.

In this aspect, particles with a particle size of less than 1.0 μm to more than 1 nm may also be present in the surface layer A. Since the surface layer A substantially does not contain particles with a particle diameter of 1.0 μm or more, such as inorganic particles, it is possible to reduce defects caused by the shape of particles in the base material being transferred to the resin sheet.

In one aspect, since the surface layer A does not contain particles with a particle size less than 1.0 μm, it is possible to more effectively prevent the shape of particles in the base material from being transferred to the resin sheet and causing defects.

In one aspect, the polyester film base material is preferably a laminated film having a surface layer A that does not substantially contain inorganic particles on at least one side. This can more effectively prevent the particle shape in the base material from being transferred to the resin sheet and causing defects.

For example, the surface layer A that does not substantially contain particles having a particle diameter of less than 1.0 μm is preferably in a state that also does not substantially contain particles having a particle diameter of 1.0 μm or more.

Here, in the present invention, "substantially does not contain particles" means that, for example, in the case of inorganic particles less than 1.0 μm, when the inorganic element is quantified by fluorescence X-ray analysis, it is 50 ppm or less, preferably 50 ppm or less. 10 ppm or less, preferably a content below the detection limit. This is because even if particles are not actively added to the film, contaminants originating from external foreign matter or contaminants attached to the production line or equipment during the raw resin or film manufacturing steps may be peeled off and mixed into the film. . In addition, "substantially does not contain particles with a particle size of 1.0 μm or more" means that particles with a particle size of 1.0 μm or more are not actively contained.

In the case of a laminated polyester film composed of a multilayer structure of two or more layers, it is preferable to have a surface layer B that may contain inorganic particles on the opposite side of the surface layer A that does not substantially contain inorganic particles.

As a laminated structure, if the layer on the side where the release layer is coated is called layer A, the layer on the opposite side is called layer B, and the core layer other than surface layer A and surface layer B is called layer C, the thickness direction can be listed as follows: The layer structure is a laminated structure of release layer/A/B or release layer/A/C/B. Of course, the C layer can also have a plurality of layer structures. In addition, the surface layer B may not contain inorganic particles. In this case, in order to provide sliding properties when the film is rolled into a roll, it is preferable to provide a coating layer containing at least inorganic particles and a binder on the surface layer B.

In the polyester film base material of the present invention, it is preferable that the surface layer B (the surface opposite to the surface coated with the release layer) contains inorganic particles from the viewpoint of the sliding properties of the film and the ease of air removal. , it is especially preferable to use silica particles and/or calcium carbonate particles. The content of the inorganic particles contained in the surface layer B is preferably 5,000 ppm or more and 15,000 ppm or less in total.

At this time, the regional average surface roughness (Sa) of the surface layer B film is preferably in the range of 1 nm or more and 40 nm or less. More preferably, it is in the range from 5 nm to 35 nm. When the total amount of silica particles and/or calcium carbonate particles is 5000 ppm or more and the Sa particle size is 1 nm or more, when the film is rolled into a roll, the air can be dispersed uniformly, and the rolled appearance and flatness are good. , thus suitable for manufacturing ultra-thin layer ceramic green sheets. In addition, when the total amount of silica particles and/or calcium carbonate particles is 15,000 ppm or less and the Sa system is 40 nm or less, aggregation of the lubricant is unlikely to occur and there will be no coarse protrusions. Therefore, in ultra-thin layer ceramic green sheets The quality is stable and better during manufacturing.

As the particles contained in the B layer, in addition to silica and/or calcium carbonate, inert inorganic particles and/or heat-resistant organic particles may also be used. However, from the viewpoint of transparency and cost, it is more preferable to use silica particles and/or calcium carbonate particles. Examples of other usable inorganic particles include alumina-silica composite oxide particles, hydroxyapatite particles, and the like. Examples of heat-resistant organic particles include crosslinked polyacrylic particles, crosslinked polystyrene particles, benzoguanamine particles, and the like. In addition, when silica particles are used, porous colloidal silica is preferred, and when calcium carbonate particles are used, from the viewpoint of preventing the lubricant from falling off, polyacrylic acid-based polymers are preferred. Light calcium carbonate surface-treated with molecular compounds.

The average particle diameter of the inorganic particles added to the surface layer B is preferably from 0.1 μm to 2.0 μm, and particularly preferably from 0.3 μm to 1.0 μm. If the average particle size of the inorganic particles is 0.1 μm or more, the release film will have good sliding properties, so it is preferable. In addition, as long as the average particle size is 2.0 μm or less, there is no risk of adversely affecting the smoothness of the surface of the release layer, and therefore there is no risk of pinholes being generated in the ceramic green sheet, so it is preferable.

In addition, in order to improve the adhesion and antistatic properties of the subsequently coated release layer, the surface of surface layer A and/or surface layer B can also be added before stretching or after uniaxial stretching in the film forming step. The film is provided with a coating layer and can also be subjected to corona treatment, etc.

In the present invention, the peelability of the ceramic green sheet of the polysilicone release polyester film can be measured in the following manner, for example. The prepared slurry is evenly coated on the coating layer of the release polyester film so that the thickness becomes 2 μm after drying, and then dried to form a ceramic green sheet. Next, the release polyester film on which the ceramic green sheet is formed is cut into a size such as 25 mm × 150 mm, and an adhesive tape is attached to the side of the ceramic green sheet to prepare a test piece.

The obtained test piece is subjected to humidity control at, for example, 23°C and 50% humidity for 24 hours, and then the ceramic green sheet (adhesive tape side) is peeled off using a tensile testing machine at a peeling angle of 90° and a peeling speed of 10m/min, and the measurement is performed. Peel strength. The peel strength of the ceramic green sheet is preferably less than 0.60 N/mm under the conditions of the examples, for example, and more preferably 0.55 N/mm or less.

[Coating composition for release] The release coating composition of the present invention contains: an aqueous dispersion (1) of polysilicone (A). The number average molecular weight of the polysilicone (A) is 25,000 or more, and contains more than 3 in one molecule. Alkenyl group; aqueous dispersion (2) of polysiloxy (B), the number average molecular weight of the aforementioned polysiloxy (B) is 25,000 or less, and only has alkenyl groups at both ends in one molecule; polysiloxy (B) The aqueous dispersion (3) of C), the polysiloxane (C) has a number average molecular weight of 10,000 or less and has hydrogen atoms directly bonded to Si atoms represented by Si-H groups; and a platinum-based catalyst .

The alkenyl group-containing polysiloxane component in the present invention is composed of at least two components with different molecular weights.

(Alkenyl-containing polysiloxane (A)) Polysilicone (A) (hereinafter sometimes referred to as "polysilicone (A)" or "alkenyl group-containing polysilicone (A)") is used in the present invention and has a number average molecular weight of 25,000 or more and 1 The molecule contains more than 3 alkenyl groups.

The alkenyl group-containing polysiloxane (A) preferably has alkenyl groups at both terminals and side chains in one molecule.

In addition, the alkenyl group of the alkenyl group-containing polysiloxy (A) is at least 3 or more in one molecule, but may be 4 or more, 5 or more, 6 or more, etc. In addition, the upper limit of the number of alkenyl groups in the alkenyl group-containing polysiloxane (A) is sufficient as long as the effect of the present invention can be exerted. For example, it can be set to 30 or less, 20 or less, 15 or less, 10 or less, etc. When the alkenyl group-containing polysiloxane (A) has two or less alkenyl groups per molecule, the cross-linking reactivity decreases and the peeling of the ceramic green sheet becomes severe.

Examples of the alkenyl group-containing polysiloxane (A) include organopolysiloxanes having a structure represented by the following general formula (I). R ¹ _a R ² _b SiO _(4-ab)/2 (I) (In formula (I), R ¹ is an alkenyl group with 2 to 8 carbon atoms, and R ² is an alkenyl group with 1 carbon number selected from an alkyl group or an aryl group. to 16 monovalent saturated hydrocarbon groups, a ranges from 0 to 3, b ranges from 0 to 2, and each represents an integer satisfying a+b≦3.)

The alkenyl group-containing polysiloxane (A) may have a linear structure or a branched chain structure, may have a partially cross-linked structure, or may be a mixture thereof.

Examples of the alkenyl group having 2 to 8 carbon atoms represented by R ¹ include vinyl, allyl, butenyl, pentenyl, hexenyl, and the like. Among these, vinyl is particularly preferred.

Examples of the alkyl group represented by R ² include methyl, ethyl, propyl, butyl, etc., and examples of the aryl group include phenyl, tolyl, etc. Among them, from the viewpoint of light peelability, it is preferable that 80 mol% or more of the substituents of R ² be methyl groups.

In addition, relative to all the silicon atoms in the aforementioned alkenyl group-containing polysiloxane (A), for example, the silicon atoms having an alkenyl group are in the range of 0.05 mol% to 20 mol%, depending on the hardening speed and pot life of the composition. ) is better from the point of view. When the proportion of silicon atoms having an alkenyl group is less than the lower limit, the curing speed of the composition may decrease, making it difficult to efficiently form a cured polysiloxane coating during film formation. In addition, when the ratio of silicon atoms having an alkenyl group exceeds the upper limit, the pot life of the composition may be shortened.

Examples of the alkenyl group-containing polysiloxane (A) include polysiloxane represented by the following formula (1-1). [Chemical formula 1] (In formula (1-1), m is 2.5 and n is 400.)

The aforementioned alkenyl group-containing polysiloxane (A) can be produced by a known method. In addition, the alkenyl group-containing polysiloxane (A) of the present invention is preferably contained in the aforementioned composition in the state of an aqueous dispersion (aqueous dispersion (1)).

When the alkenyl group-containing polysiloxane (A) is made into an aqueous dispersion (aqueous dispersion (1)), the alkenyl group-containing polysiloxane in 100 parts by mass of the aqueous dispersion (1) The content of (A) may be, for example, 1 to 80 parts by mass, 3 to 75 parts by mass, 5 to 70 parts by mass, or 10 to 65 parts by mass. or less than 15 parts by mass or more and less than 60 parts by mass, etc. When the content is 10 parts by mass or less, the long-term stability of the emulsion may deteriorate, and when the content is 80 parts by mass or more, the viscosity may become high and the dispersibility may deteriorate.

The number average molecular weight of the alkenyl group-containing polysiloxy (A) is 25,000 or more, and may be, for example, 26,000 or more, 27,000 or more, 28,000 or more, 30,000 or more, etc. The upper limit of the number average molecular weight of the alkenyl group-containing polysiloxane (A) is sufficient as long as the effect of the present invention can be exerted. For example, it can be set to 45,000 or less, 40,000 or less, or the like. In addition, if the number average molecular weight is 50,000 or more, the emulsion of the aqueous dispersion may be unstable.

When the total solid content of the alkenyl group-containing polysiloxane (A) and polysiloxane (B) and the Si-H group-containing polysiloxane (C) is 100 parts by mass, the alkenyl group-containing polysiloxane (C) The content of the base polysiloxane (A) is preferably from 80 parts by mass to 96 parts by mass, for example, from 85 parts by mass to 95 parts by mass, from 88 parts by mass to 94 parts by mass, or 90 parts by mass. More than 92 parts by mass or less. If the aforementioned content is more than 96 parts by mass, the polymer polysiloxane will increase and the cross-linking density will decrease. In addition, if the aforementioned content is 80 parts by mass or less, the crosslinking point between the high molecular weight polysiloxane and the low molecular weight polysiloxane will be reduced, resulting in a decrease in the crosslinking density.

(Alkenyl-containing polysiloxane (B)) Polysilicone (B) (hereinafter sometimes referred to as "polysilicone (B)" or "alkenyl group-containing polysilicone (B)") is used in the present invention. The number average molecular weight is 25,000 or less and is 1 The molecule only has alkenyl groups at both ends.

The alkenyl group-containing polysiloxane (B) has alkenyl groups only at both terminals in one molecule. It is possible for the aforementioned low molecular weight alkenyl group-containing polysiloxane (B) to complete the crosslinking reaction of the crosslinked network of the aforementioned high molecular weight alkenyl group-containing polysiloxane (A). It is speculated that the crosslinking can be achieved as much as possible The density is maximized and light peeling from the ceramic green sheet becomes possible. However, this is only the case of the aforementioned mechanism, and the scope of the patent application is not limited to this.

Examples of the alkenyl group-containing polysiloxane (B) include organopolysiloxanes having a structure represented by the following general formula (I′). R ^1' _a' R ^2' _b' SiO _(4-a'-b')/2 (I') (In formula (I'), R ^1' is an alkenyl group having 2 to 8 carbon atoms, and R ^2' It is a monovalent saturated hydrocarbon group with 1 to 16 carbon atoms selected from an alkyl group or an aryl group, a' is 0 to 1, b' is 0 to 2, and each represents an integer satisfying a'+b'≦3.)

The alkenyl group-containing polysiloxane (B) may have a linear structure or a branched chain structure, may have a partially cross-linked structure, or may be a mixture thereof.

Examples of the alkenyl group having 2 to 8 carbon atoms represented by R ^1′ include vinyl, allyl, butenyl, pentenyl, hexenyl, and the like. Among these, vinyl is particularly preferred. In addition, the aforementioned alkenyl group-containing polysiloxane (B) has alkenyl groups only at both terminals in one molecule.

Examples of the alkyl group represented by R ^2' include methyl, ethyl, propyl, butyl, and the like, and examples of the aryl group include phenyl, tolyl, and the like. Among them, from the viewpoint of light release properties, it is preferable that at least 80 mol% of the substituents of R ^2' be methyl groups.

In addition, relative to all the silicon atoms in the aforementioned alkenyl group-containing polysiloxane (B), for example, the silicon atoms having an alkenyl group are in the range of 0.05 mol% to 20 mol%. From the perspective of the hardening speed and pot life of the composition, See better.

Examples of the alkenyl group-containing polysiloxane (B) include polysiloxane represented by the following formula (1-2). [Chemical formula 2] (In formula (1-2), n is 200.)

The number average molecular weight of the alkenyl group-containing polysiloxy (B) is 25,000 or less. For example, it may be 24,000 or less, 23,000 or less, 22,000 or less, 21,000 or less, 20,000 or less, 19,000 or less, 18,000 or less, 17,000 or less, etc. The lower limit of the number average molecular weight of the alkenyl group-containing polysiloxane (B) is sufficient as long as the effect of the present invention can be exerted. For example, it can be set to 10,000 or more, 11,000 or more, 12,000 or more, etc. When the molecular weight is 25,000 or more, it is almost the same as polysiloxane (A), so the crosslinking density cannot be improved. On the other hand, when the molecular weight is too small, it is difficult to form between polysiloxane (A). cross-linked network.

The aforementioned alkenyl group-containing polysiloxane (B) can be produced by a known method. In addition, the alkenyl group-containing polysiloxane (B) is preferably contained in the composition in the state of an aqueous dispersion (aqueous dispersion (2)).

When the alkenyl group-containing polysiloxane (B) is made into an aqueous dispersion (aqueous dispersion (2)), the alkenyl group-containing polysiloxane in 100 parts by mass of the aqueous dispersion (2) The content of (B) may be, for example, 1 to 80 parts by mass, 3 to 70 parts by mass, 5 to 65 parts by mass, or 10 to 60 parts by mass. or less than 15 parts by mass or more and less than 55 parts by mass, etc. When the content is 10 parts by mass or less, the long-term stability of the emulsion may deteriorate, and when the content is 80 parts by mass or more, the viscosity may become high and the dispersibility may deteriorate.

When the total solid content of the alkenyl group-containing polysiloxane (A) and polysiloxane (B) and the Si-H group-containing polysiloxane (C) is 100 parts by mass, the alkenyl group-containing polysiloxane (C) The content of the base polysiloxane (B) is preferably from 2 parts by mass to 20 parts by mass, for example, from 3 parts by mass to 18 parts by mass, from 4 parts by mass to 15 parts by mass, or 5 parts by mass. More than 10 parts by mass or less.

(Si-H group-containing polysiloxane (C)) In the present invention, the polysiloxane (C) having a hydrogen atom directly bonded to the Si atom represented by the Si-H group (hereinafter sometimes referred to as "polysiloxane") Examples of "silicone (C)" and "Si-H group-containing polysiloxane (C)") include organohydrogen polysiloxane having a structure represented by the following general formula (II). R ³ _c H _d SiO _(4-cd)/2 (II) (In formula (II), R ³ is a monovalent saturated hydrocarbon group with 1 to 16 carbon atoms selected from an alkyl group or an aryl group, and c is 0 to 2 , d ranges from 1 to 3, and respectively represent integers satisfying c+d≦3.)

The aforementioned Si-H group-containing polysiloxane (C) may have either a linear structure or a branched chain structure.

Examples of the alkyl group represented by R ³ include methyl, ethyl, propyl, butyl, etc. Examples of the aryl group include phenyl, tolyl, etc. Among them, from the viewpoint of light peelability, it is preferable that 50 mol% or more of the substituents of R ³ be methyl groups.

From the viewpoint of hardening properties, the Si-H group-containing polysiloxane (C) preferably has three, preferably five or more hydrogen atoms bonded to Si atoms in one polysiloxane molecule. atom.

Examples of the Si-H group-containing polysiloxane (C) include polysiloxane represented by the following formula (2). [Chemical formula 3] (In formula (2), o represents 30 and p represents 35.)

The aforementioned Si-H group-containing polysiloxane (C) can be produced by a known method. In addition, the Si-H group-containing polysiloxane (C) of the present invention is preferably contained in the aforementioned composition in the state of an aqueous dispersion (aqueous dispersion (3)).

When the Si-H group-containing polysiloxane (C) is made into an aqueous dispersion (aqueous dispersion (3)), the alkenyl group-containing polysiloxane (C) in 100 parts by mass of the aqueous dispersion (3) The content of silicon oxygen (C) may be, for example, 1 mass part or more and 80 mass parts or less, 3 mass parts or more and 70 mass parts or less, 5 mass parts or more and 60 mass parts or less, or 8 mass parts or more and 55 mass parts or more. Parts by mass or less or more than 10 parts by mass and less than 50 parts by mass, etc. When the content is 10 parts by mass or less, the long-term stability of the emulsion may deteriorate, and when the content is 80 parts by mass or more, the viscosity may become high and the dispersibility may deteriorate.

The number average molecular weight of the Si-H group-containing polysiloxane (C) is 10,000 or less, for example, it may be 8,000 or less, 7,000 or less, 6,000 or less, etc. When the number average molecular weight is 10,000 or more, the function as a cross-linking agent is insufficient and the cross-linking density is reduced. In addition, the lower limit of the number average molecular weight of the Si-H group-containing polysiloxane (C) is not particularly limited as long as the effect of the present invention can be exerted. For example, it can be set to 300 or more, 500 or more, or 1000 or more. , 2000 and above, etc.

When the total solid content of the alkenyl group-containing polysiloxane (A) and polysiloxane (B) and the Si-H group-containing polysiloxane (C) is 100 parts by mass, the Si-containing The content of -H-based polysiloxy (C) is preferably from 2 parts by mass to 20 parts by mass, for example, from 3 parts by mass to 18 parts by mass, from 4 parts by mass to 15 parts by mass, or 5 parts by mass. From more than 10 parts by mass to less than 10 parts by mass, etc. When the content is less than 2 parts by mass, the hardening reaction may be difficult to proceed and sufficient coating film hardness may not be obtained. When the content exceeds 20 parts by mass, Si-H may be excessively precipitated on the surface. Strongly adheres to the green sheet, resulting in heavy peeling.

(ratio of the number of Si-H groups to the number of alkenyl groups) The ratio of the number of Si-H groups to the number of alkenyl groups (the number of alkenyl groups in polysiloxy (A) and polysiloxy (B)) in the release coating composition of the present invention (the number of Si-H groups /number of alkenyl groups) is preferably in the range of 1.0 to 2.0. If the aforementioned ratio does not reach the lower limit, excess alkenyl groups may remain in the formed coating layer, so the peel strength is likely to change over time, the cross-linking density decreases, and the uniformity of the peel force and the residual adhesion rate decrease. In addition, if the aforementioned ratio exceeds the upper limit, highly reactive Si-H groups may remain in the formed coating layer, thereby causing an increase in peeling force.

(Polysilicone content) In the release coating composition of the present invention, based on the solid content mass of the aforementioned composition, the solid content of the alkenyl group-containing polysiloxane (the solid content of polysiloxane (A) and polysiloxane (B) The total amount of the solid content of the Si-H group-containing polysiloxane (C) is preferably 70 mass % or more. In addition, a more preferable content of each polysiloxane solid component is 80 mass % or more and 97 mass % or less. Here, the polysiloxane solid content refers to the amount excluding the aqueous solvent, and the solid content mass of the composition refers to the total amount of solid content of each additive. If the total amount of the polysilicone solid content is less than the lower limit, the area covered by the polysilicone relative to the film surface on which the coating film is formed may become smaller, and the peeling force may become heavier, resulting in uneven peeling force.

(aqueous solvent) As an aqueous solvent for forming each polysiloxane aqueous dispersion of the present invention, water is preferably used. By using an aqueous solvent, the polysiloxane release layer can be formed without the use of explosion-proof equipment and organic solvent recovery equipment during the production process of the release film.

(emulsifier) In order to improve the stability and shear resistance of the aqueous dispersion, each aqueous dispersion can be made with an emulsifier. As the emulsifier, a nonionic emulsifier that does not affect the hardening reaction of polysiloxane is preferred. It is possible that ionic emulsifiers may affect the hardening reaction of polysiloxane. In addition, they may be localized in the coating film, such as bleeding out on the surface, thereby affecting the release properties.

As a nonionic emulsifier, the HLB value (Hydrophile-Lipophile Balance; hydrophile-lipophile balance value) is preferably in the range of 8 or more and 18 or less. Examples include alkylene oxides selected from higher alcohols and higher fatty acids. Adducts, esters of alkylene oxide adducts of higher fatty acids and alcohols, alkylene oxide adducts of alkanolamides, alkylene oxide adducts of sorbitan esters, epoxy glycerides of higher fatty acids At least one alkylene oxide addition type such as an alkane adduct. These can be used individually or in combination of 2 or more types. Here, the HLB value is a value calculated using Griffin's calculation formula.

Examples of alkylene oxides include ethylene oxide, propylene oxide, and butylene oxide. One of these may be used, or a plurality of them may be used. When using a plurality of them, regardless of the block or random addition form, the HLB value is preferably in the range of 8 or more and 18 or less, and more preferably in the range of 10 or more and 15 or less. Among these nonionic emulsifiers, preferred examples include polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, and the like. If a nonionic emulsifier whose HLB value deviates from the above range is used as the emulsifier of the polysilica aqueous dispersion, the emulsification and dispersion power and the stability of the aqueous dispersion may decrease. The nonionic emulsifier is preferably used in the range of 0.1 mass % or more and 20 mass % or less based on the total solid content, more preferably in the range of 0.2 mass % or more and 15 mass % or less, and still more preferably in the range of 0.5 mass % or more and 10 mass % or more. Mass% or less. If it is less than the above range, emulsification tends not to be smooth, and if it is more than the above range, heavy exfoliation may occur.

(catalyst) In the release coating composition constituting the coating layer of the present invention, in order to cause the above-mentioned polysilicone (A) and/or the above-mentioned polysilicone (B) to perform an addition reaction with the above-mentioned polysilicone (C), it is better to It is best to use a catalyst, especially a platinum-based catalyst.

(Platinum series catalyst) As the platinum-based catalyst, a publicly known catalyst can be used, and examples thereof include platinum chloride and chloroplatinic acid. Considering the dispersibility of the aforementioned platinum catalyst to polysiloxane, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum complex (karstedt) can be used Catalyst) can ensure uniform dispersion by simultaneously dispersing polysiloxane while emulsifying it. These can be used individually or in combination of 2 or more types.

Regarding the amount of platinum-based catalyst, relative to the aqueous dispersion (1) of polysilicone (A), the aqueous dispersion (2) of polysilicone (B), and the aqueous dispersion of polysilicone (C) (3) The preferable content range of the total mass of platinum element is from 120 ppm to 800 ppm. By setting it within the aforementioned range, polysiloxane can be sufficiently hardened. Furthermore, the generation of polysiloxane aggregates can be suppressed, and a release polyester film with excellent surface properties can be obtained. If the mass ratio of the platinum element exceeds the upper limit, the addition reaction between the alkenyl group and the Si-H group is accelerated, and polysiloxane aggregates tend to be generated. From the aforementioned viewpoint, the platinum-based catalyst amount is, for example, 600 ppm or less, 500 ppm or less, 300 ppm or less, 250 ppm or less, and the like. In addition, if the mass ratio of the platinum element is less than the lower limit, the addition reaction cannot proceed, which tends to cause poor hardening of the polysiloxane. From the above point of view, the amount of platinum-based catalyst is, for example, 130 ppm or more, 140 ppm or more, 150 ppm or more, 200 ppm or more, etc.

cross-linking reaction inhibitor In order to suppress the activity of the platinum-based catalyst at room temperature, it is preferable to include a cross-linking reaction inhibitor in the aqueous coating composition. The aforementioned cross-linking reaction inhibitor is preferably a cross-linking reaction inhibitor having an alkynyl group. The cross-linking reaction inhibitor having an alkynyl group is not particularly limited as long as it has an alkynyl group. Specific examples include 1-ethynyl-1-cyclohexanol and 4-ethyl-1-octyne-3. -Alcohol, 3-methyl-1-dodecyn-3-ol, 3,7,11-trimethyl-1-dodecyn-3-ol, 1,1-diphenyl-2-propyne -3-ol, 3-ethyl-6-ethyl-1-nonyn-3-ol, 3-methyl-1-pentadecene-3-ol, 2,5-dimethyl-3-hexane Alkyne-2,5-diol, 3-phenyl-1-butyn-3-ol. Preferred examples of the alkynyl group include an ethynyl group. These can be used individually or in combination of 2 or more types. In the present invention, since an aqueous emulsion coating composition is used, it is preferable to use the exemplified alkynyl group and Hydroxyl cross-linking reaction inhibitor.

Relative to the amount of the aqueous coating composition used to form the release layer, the content of the cross-linking reaction inhibitor is preferably from 5 ppm to 1000 ppm, more preferably from 10 ppm to 700 ppm, and further preferably from 20 ppm to 500 ppm. When the content of the cross-linking reaction inhibitor is more than the lower limit, the pot life becomes longer, the addition hardening reaction of polysiloxane becomes difficult to proceed at room temperature, and polysiloxane aggregates tend to be difficult to generate. In addition, if the content of the cross-linking reaction inhibitor is less than the upper limit, it will be difficult for the polysiloxane to transfer to the target material after peeling off the target material, and the amount of the reaction inhibitor volatilized during heat treatment will be reduced, so it is difficult to cause internal generation of the cross-linking reaction inhibitor in the oven. of pollution.

In addition, the content of the cross-linking reaction inhibitor is preferably 6 times or less, more preferably 5 times or less, and particularly preferably 4 times or less relative to the mass of the platinum element, for example, the mass of the platinum element.

The cross-linking reaction inhibitor having an ethynyl group is not particularly limited as long as it has an ethynyl group. However, since a water-based coating composition is used in the present invention, the solubility with water and the coordination ability with platinum From the viewpoint of balance and volatility, it is preferable to use a cross-linking reaction inhibitor having an ethynyl hydroxyl group represented by 1-ethynylcyclohexanol.

(other ingredients) To the release coating composition of the present invention, adhesion imparting agents to the base material, colorants, ultraviolet absorbers, particles, antistatic agents, etc. may be further added within the scope that does not impair the subject of the present invention.

(Preparation of polysilicone aqueous dispersion) When preparing each polysilicone aqueous dispersion of the present invention, a method of emulsifying using the polysilicone component, an aqueous solvent, and an emulsifier described above can be used. These ingredients can be emulsified using known methods, for example: using a homogenizer, vacuum emulsification mixer (AGI-HOMO MIXER), ultra planetary mixer and other stirring devices to mix the pre-made polysiloxane and Methods for mechanical emulsification of emulsifiers and other ingredients as necessary in aqueous media.

In addition, the size of the stirring blades, stirring speed and stirring time can be adjusted to adjust the particle size of the aqueous dispersion. The average particle size of each polysiloxy aqueous dispersion of the present invention is preferably 200 nm or less, more preferably 100 nm or more and 200 nm or less.

[Coating layer] In the present invention, a coating layer (release layer) is formed on at least one side of a polyester film using the release coating composition of the present invention. The coating layer (release layer) of the present invention is formed by coating the polyester film with the release coating composition and then drying it.

In the present invention, the thickness of the coating layer is preferably from 5 nm to 70 nm as the thickness after drying. If the thickness of the coating layer is less than the lower limit, the release characteristics may become insufficient. On the other hand, if the thickness of the coating layer exceeds the upper limit, in addition to the increase in peel strength, the coating liquid also needs to be highly concentrated. The amount of cloth increases, so it tends to be difficult to apply.

When coating the release coating composition of the present invention on a polyester film, an aqueous coating liquid containing the aforementioned composition is prepared. The solid content concentration of the aqueous coating liquid is based on the mass of the aforementioned coating liquid. Preferably, it is 20 mass % or less, and further preferably, it is 1 mass % or more and 10 mass % or less. If the solid content concentration in the aqueous coating liquid does not reach the lower limit, the coating properties for the polyester film may be insufficient. In addition, when the solid content concentration exceeds the upper limit, the stability of the coating liquid and the appearance of the coating layer may deteriorate. As an aqueous solvent for adjusting the solid content concentration, water can be preferably used.

Coating of the polyester film with the aqueous coating liquid can be carried out at any stage, but it is preferably carried out during the manufacturing process of the polyester film, and more preferably, it is coated on the polyester film before the completion of alignment crystallization.

Here, the so-called polyester film before the crystal alignment is completed includes: an unstretched film, and the unstretched film is stretched in the longitudinal direction (hereinafter sometimes referred to as the film continuous film forming direction, the longitudinal direction, and the MD direction) or the transverse direction (hereinafter referred to as the MD direction). are sometimes referred to as a uniaxially stretched film oriented in any direction orthogonal to the longitudinal direction, the width direction, or the TD direction), and a biaxially stretched film oriented by low-magnification stretching of an unstretched film in both the longitudinal and transverse directions. Axial stretched film (biaxially stretched film before final stretching in the longitudinal or transverse direction to complete alignment crystallization), etc. Among these, it is preferable to apply an aqueous coating liquid of the aforementioned composition to an unstretched film or a uniaxially stretched film oriented in one direction, and directly perform longitudinal stretching and/or transverse stretching and heat fixing in this state. So-called in-line coating. The coating layer can be dried by a post-coating extension step or heat fixation treatment, and a drying step can also be applied if necessary. In addition, when a catalyst is used to harden the composition to obtain a hardened coating, the composition can be hardened by a stretching step or a heat fixing treatment. However, a further hardening step can also be performed if necessary.

When applying an aqueous coating liquid to a polyester film, for example, as a pretreatment to improve coatability, it is preferable to apply physical treatments such as corona surface treatment, flame treatment, and plasma treatment to the film surface, or to The aforementioned emulsifier is used together with the composition as a wetting agent.

As the coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife method, an impregnation method, and a curtain coating method can be used alone or in combination. wait.

＜Manufacturing method of polysilicone release polyester film＞ The manufacturing method of the polysilicone release polyester film of the present invention includes the step of using a release coating composition to form a coating layer. The release coating composition includes: a water dispersion of polysilicone (A) Body (1), the number average molecular weight of the aforementioned polysiloxane (A) is more than 25,000, and contains more than 3 alkenyl groups in one molecule; the aqueous dispersion (2) of the polysiloxane (B), the aforementioned polysiloxane The number average molecular weight of oxygen (B) is 25,000 or less, and one molecule has alkenyl groups only at both ends; the aqueous dispersion (3) of polysilicone (C), the number average molecular weight of the aforementioned polysilicone (C) is less than 10,000, and has a hydrogen atom directly bonded to a Si atom represented by a Si-H group; and a platinum-based catalyst; in When the total solid content of silica (C) is 100 parts by mass, it includes 80 parts by mass or more of the aforementioned polysiloxane (A) and 2 or more parts by mass and 20 parts by mass or less of the aforementioned polysiloxane (B). ) and 2 parts by mass or more and 20 parts by mass or less the aforementioned polysiloxane (C).

The method for manufacturing a silicone release polyester film of the present invention can efficiently and simply obtain a silicone release polyester film having the aforementioned characteristics. In addition, the manufacturing method shown here is an example, and this invention is not limited to this.

In the above-mentioned manufacturing method, regarding each structure, the description related to the above-mentioned polysilicone release polyester film and the like in this specification can be applied as appropriate.

As the step of forming a coating layer using a release coating composition of an aqueous dispersion in the above-mentioned manufacturing method, any method is as long as it is a method of forming a coating layer on a film using a release coating composition of an aqueous dispersion. Known techniques can be used appropriately. [Example]

The present invention will be described in detail through examples. However, the present invention is not limited to the following examples. In addition, the physical properties and characteristics in the examples were measured or evaluated by the following methods. In addition, when "parts" are noted, it means "parts by mass".

Each measurement, evaluation, etc. in the Examples were performed in the following manner.

To determine the peelability of ceramic green sheets, 100 parts by mass of barium titanate (BaTiO ₃ ), 7 parts by mass of polyvinyl butyral, and o-phenylene were added to a mixed solvent of toluene: ethanol = 1:1 (volume ratio). 3 parts by mass of dioctyl phthalate was dispersed using a ball mill to prepare a slurry.

The obtained slurry was evenly applied on the coating layer of the release polyester film so that the thickness after drying became 2 μm, and then dried to form a ceramic green sheet. The release polyester film on which the ceramic green sheet was formed was cut into 25 mm × 150 mm, and an adhesive tape (manufactured by Nitto Denko Co., Ltd.; trade name "31B tape") was attached to the side of the ceramic green sheet to prepare a test piece.

The obtained test piece was humidified at 23°C and 50% humidity for 24 hours. Then, using a tensile testing machine, the ceramic green sheet (31B tape side) was peeled off at a peeling angle of 90° and a peeling speed of 10m/min, and the peeling was measured. intensity. The peel strength of the ceramic green sheet was evaluated based on the following indexes. 〇: Peel strength does not reach 0.60N/mm ×: Peel strength is 0.60N/mm or more

[Example 1 to Example 2, Comparative Example 1 to Comparative Example 5] Molten polyethylene terephthalate ([eta]=0.64dl/g, Tg=78°C) containing 0.1% by mass of calcium carbonate particles with an average particle diameter of 0.7μm was extruded through a die by a general method. An unstretched film was formed by cooling with a cooling roller, and then stretched to 3.6 times in the longitudinal direction. The aqueous coating liquid (solid An aqueous dispersion with a component concentration of 3% by mass) was evenly coated on the surface of the film.

Next, the coating film was dried at 115°C for about 5 seconds and stretched to 4.5 times in the transverse direction at 145°C, and then heat-fixed at 230°C for about 5 seconds to obtain the properties shown in Table 1. The coating layer shown is a 25 μm biaxially stretched polyester film.

(Aqueous dispersion (1) of alkenyl group-containing polysiloxane (A)) Using an integral emulsification device in a stirrable container (manufactured by New Perticle Laboratory Co., Ltd.; device name "Super Planetary Mixer"), polysiloxane having an alkenyl group represented by the following formula (1-1) (average quantity A raw material consisting of 98% by mass (molecular weight: 28000) and 2% by mass of polyoxyethylene lauryl ether (manufactured by Kao Co., Ltd., trade name "EMULGEN 109P") as a surfactant was mechanically emulsified in an aqueous medium to obtain a solid Composition: 20% by mass of alkenyl-containing polysiloxane aqueous dispersion. In addition, the emulsion particle size can be adjusted by adjusting the stirring speed and stirring time during emulsification.

[Chemical formula 4] (In formula (1-1), m is 2.5 and n is 400.)

(Aqueous dispersion (2) of alkenyl group-containing polysiloxane (B)) Using an integral emulsification device in a stirrable container (manufactured by New Perticle Laboratory Co., Ltd.; device name "Super Planetary Mixer"), polysiloxane having an alkenyl group represented by the following formula (1-2) (average quantity A raw material consisting of 98% by mass (molecular weight: 14000) and 2% by mass of polyoxyethylene lauryl ether (manufactured by Kao Co., Ltd., trade name "EMULGEN 109P") as a surfactant was mechanically emulsified in an aqueous medium to obtain a solid Composition: 20% by mass of alkenyl-containing polysiloxane aqueous dispersion. In addition, the emulsion particle size can be adjusted by adjusting the stirring speed and stirring time during emulsification.

[Chemical formula 5] (In formula (1-2), n is 200.)

(Aqueous dispersion (3) of polysiloxane (C) having Si-H groups) Using an integral emulsification device in a stirrable container (manufactured by New Perticle Laboratory Co., Ltd.; device name "Super Planetary Mixer"), the polysiloxane (number average molecular weight) having a hydrogen group represented by the following formula (2) is: 5000) and 2 mass% of polyoxyethylene lauryl ether (manufactured by Kao Co., Ltd., trade name "EMULGEN 109P") as a surfactant were mechanically emulsified in an aqueous medium to obtain a solid content of 10 Mass % of Si-H group-containing polysiloxane aqueous dispersion. In addition, the emulsion particle size can be adjusted by adjusting the stirring speed and stirring time during emulsification.

[Chemical formula 6] (In formula (2), o represents 30 and p represents 35.)

(Platinum series catalyst) Through a platinum-based catalyst containing a reaction inhibitor: an isopropyl alcohol solution of chloroplatinic acid (in this composition, the amount of platinum metal in mass units is 500ppm), polyoxyethylene lauryl ether (Kao) as a surfactant Co., Ltd.; trade name "EMULGEN 109P") 99.75% by mass, cross-linking reaction inhibitor (0.2% by mass 1-ethynylcyclohexanol), and pure water to prepare an aqueous dispersion with a solid content of 10% by mass. Since this platinum The cross-linking reaction inhibitor in the catalyst is preferentially coordinated, so the catalyst effect can be delayed until the reaction inhibitor evaporates.

(Polysilicone coating liquid preparation) As the release coating composition, according to the formulation shown in Table 1, a composition consisting of alkenyl group-containing polysiloxane aqueous dispersion/Si-H group-containing polysiloxane aqueous dispersion/platinum-based catalyst was used. The composition was diluted with water to a solid content concentration of 10% in the coating liquid so as to have a layer thickness of 50 nm, and a coating liquid was prepared.

Table 1 shows the above formula and the above results. In addition, the numerical value of each polysiloxane represents the mass part of solid content.

[Table 1] unit Example 1 Example 2 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Solid content ratio of polysilicone (A) wt% 80 90 80 80 90 90 50 50 80 Solid content ratio of polysiloxane (B) wt% 10 5 20 0 10 0 40 10 10 Solid content ratio of polysiloxane (C) wt% 10 5 0 20 0 10 10 40 10 Platinum series catalyst ppm 140 140 140 140 140 140 140 140 90 Ceramic Green Sheet Peelability mN/mm 0.49 0.52 NG (not hardened) 0.63 NG (not hardened) 0.65 0.74 0.98 0.61

As can be seen from Table 1, the film of the Example of the present invention has excellent peelability even for a very thin ceramic green sheet of 2 μm. It is presumed that this is because a specific composition including predetermined cross-linkable high molecular weight polysiloxane, low molecular weight polysiloxane and Si-H group-containing polysiloxane is used to obtain a film with excellent peelability. On the other hand, in Comparative Examples 1 to 7, crosslinking was insufficient and hardening was not performed, and as a result, appropriate light peelability could not be obtained.

Claims (10)

A polysilicone release polyester film has a coating layer formed by using a release coating composition. The aforementioned release coating composition includes: Aqueous dispersion (1) of polysilicone (A), the number average molecular weight of the polysilicone (A) is 25,000 or more, and contains more than three alkenyl groups in one molecule; Aqueous dispersion (2) of polysilicone (B), the number average molecular weight of the polysilicone (B) is 25,000 or less, and each molecule has alkenyl groups only at both ends; Aqueous dispersion (3) of polysiloxane (C), the number average molecular weight of the polysiloxane (C) is 10,000 or less, and has hydrogen atoms directly bonded to Si atoms represented by Si-H groups; and Platinum series catalyst; When the total solid content of the polysilicone (A), the polysilicone (B) and the polysilicone (C) is 100 parts by mass, 80 parts by mass or more of the polysilicone is included. Oxygen (A), not less than 2 parts by mass and not more than 20 parts by mass of the aforementioned polysiloxy (B), and not less than 2 parts by mass and not more than 20 parts by mass of the aforementioned polysiloxy (C). The polysilicone release polyester film according to claim 1, wherein the polysilicone (A) is present in one molecule and has alkenyl groups at both ends and side chains. The polysilicone release polyester film according to claim 1 or 2, wherein the alkenyl group of the polysiloxy (A) is vinyl. The polysilicone release polyester film according to claim 1 or 2, wherein the alkenyl group of the polysiloxy (B) is vinyl. The polysilicone release polyester film according to claim 1 or 2, wherein the alkenyl groups of the polysilicone (A) and the polysilicone (B) are vinyl groups. The polysilicone release polyester film according to claim 1 or 2, wherein the content of the platinum-based catalyst is 120 ppm or more relative to the total amount of the polysilicone (A) and the polysilicone (B). . The polysilicone release polyester film according to claim 1 or 2 is used for forming ceramic green sheets in the manufacture of laminated ceramic capacitors. A method for manufacturing a polysilicone release polyester film, which includes the step of using a release coating composition to form a coating layer. The release coating composition includes: Aqueous dispersion (1) of polysilicone (A), the number average molecular weight of the polysilicone (A) is 25,000 or more, and contains more than three alkenyl groups in one molecule; Aqueous dispersion (2) of polysilicone (B), the number average molecular weight of the polysilicone (B) is 25,000 or less, and each molecule has alkenyl groups only at both ends; Aqueous dispersion (3) of polysiloxane (C), the number average molecular weight of the polysiloxane (C) is 10,000 or less, and has hydrogen atoms directly bonded to Si atoms represented by Si-H groups; and Platinum series catalyst; When the total solid content of the polysilicone (A), the polysilicone (B) and the polysilicone (C) is 100 parts by mass, 80 parts by mass or more of the polysilicone is included. Oxygen (A), not less than 2 parts by mass and not more than 20 parts by mass of the aforementioned polysiloxy (B), and not less than 2 parts by mass and not more than 20 parts by mass of the aforementioned polysiloxy (C). The method for manufacturing a polysilicone release polyester film as described in Claim 8, wherein the polysilicone (A) has alkenyl groups at both ends and side chains in one molecule. The method for manufacturing a polysiloxy release polyester film as described in claim 8 or 9, wherein the alkenyl groups of the polysiloxy (A) and the polysiloxy (B) are vinyl groups.