CN120129721A

CN120129721A - Curable organopolysiloxane composition and laminate

Info

Publication number: CN120129721A
Application number: CN202380076465.2A
Authority: CN
Inventors: 远藤修司; 田中英文
Original assignee: Dow Corning Toray Co Ltd
Current assignee: DuPont Toray Specialty Materials KK
Priority date: 2022-11-18
Filing date: 2023-11-06
Publication date: 2025-06-10
Also published as: JPWO2024106246A1; WO2024106246A1; KR20250107908A; TW202424112A

Abstract

The purpose of the present invention is to provide a curable organopolysiloxane composition that is capable of forming a cured film that has stable release properties without compromising the adhesive properties of the adhesive material. The composition of the present invention comprises a linear organopolysiloxane (A) having a viscosity of 20 to 1500 mPas at 25 ℃, a higher alkenyl group having 4 to 12 carbon atoms at the terminal and side chains of the molecular chain, a linear organopolysiloxane (B) having a viscosity of 3000 to 50000 mPas at 25 ℃ and having at least two alkenyl groups having 2 to 12 carbon atoms in one molecule only at the side chains of the molecular chain, the alkenyl groups in component (B) being converted to vinyl groups (CH ₂ =CH-) in an amount of 0.1 to 0.3 mass%, an organohydrogen polysiloxane (C) having at least two silicon atom-bonded hydrogen atoms in one molecule, and a hydrosilylation catalyst (D).

Description

Curable organopolysiloxane composition and laminate

Technical Field

The present invention relates to a curable organopolysiloxane composition and a laminate produced using the composition.

Background

The curable organopolysiloxane composition is used as a material for forming a release curable film because it can form a curable film exhibiting suitable release properties for an adhesive substance. It is known to incorporate organopolysiloxanes that do not participate in the curing reaction into the composition to reduce the peel resistance to the adhesive substance. However, even in such a composition, it is difficult to sufficiently reduce the peeling resistance, but there is a problem that the residual adhesive force of the adhesive substance is lowered.

On the other hand, in recent years, a solvent-free or low-solvent composition is demanded, and as such a composition, for example, patent document 1 proposes a composition comprising a mixture of a linear diorganopolysiloxane having a viscosity of 50 to 5000mpa·s at 25 ℃ and having both ends of a molecular chain terminated with trimethylsiloxy groups, having at least two alkenyl groups having 4 or more carbon atoms in a side chain (in this siloxane, the alkenyl group content is 0.2 to 10.0 mol%) and a linear diorganopolysiloxane having a viscosity of 50 to 5000mpa·s at 25 ℃, having at least two alkenyl groups in a molecule, having both ends of a molecular chain terminated with dimethylalkenylsiloxy groups (in this siloxane, the alkenyl group content is 0.2 to 10 mol%) and having at least three silicon atoms in a molecule bonded to 1000cst, and a platinum catalyst having a viscosity of 1 to 1000mpa·s at 25 ℃ and having at least one chain and having a viscosity of at least three silicon atoms in a side chain bonded to 1000mpa·s at least one molecule, and a mixture of a platinum catalyst having two alkenyl groups having two terminal groups in a molecular chain bonded to 1000mpa·s at least 0.5 mol% and having a chain having a viscosity of at least two alkenyl groups in a1 to 10.0 mol% and a platinum group bonded to 1000 m.

However, when a release sheet having a release film produced using such a composition is left to stand under no load or is subjected to press treatment under a certain pressure, there is a problem in that the release resistance of the adhesive substance changes. If the press treatment increases the peeling resistance against the adhesive substance and causes re-peeling, the use thereof is limited.

In addition, attempts have been made to reduce the peeling resistance to the adhesive substance before and after the press treatment and to suppress the re-peeling thereof. However, there is a problem in that the residual adhesive ratio after peeling the adhesive substance is lowered.

Prior art literature

Patent literature

Patent document 1 Japanese patent laid-open No. 2000-1601102

Patent document 2 Japanese patent application laid-open No. 2002-201417

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a curable organopolysiloxane composition that is capable of forming a cured film that has stable release properties without compromising the adhesive properties of the adhesive material. Another object of the present invention is to provide a laminate having a cured film with stable peeling performance.

Solution for solving the problem

The curable organopolysiloxane composition of the present invention is characterized by comprising:

A linear organopolysiloxane (A) having a viscosity of 20 to 1500 mPas at 25 ℃ and having a higher alkenyl group having 4 to 12 carbon atoms at the terminal and side chain of the molecular chain;

A linear organopolysiloxane (B) having a viscosity of 3000 to 50000 mPa.s at 25 ℃ and having at least two alkenyl groups having 2 to 12 carbon atoms in one molecule only in side chains of the molecular chain, wherein the content of the alkenyl groups in the component (B) is 0.1 to 0.3 mass% in terms of vinyl groups (CH ₂ =CH-);

an organohydrogen polysiloxane (C) having at least two silicon atoms bonded to hydrogen atoms in one molecule, and

A catalytic amount of a hydrosilylation catalyst (D),

The mass ratio of the component (A) to the component (B), namely, the component (A)/the component (B), is 90/10-75/25,

The ratio of the number of moles of silicon atom-bonded hydrogen atoms in the component (C) to the total number of moles of higher alkenyl groups in the component (A) and alkenyl groups in the component (B) is 0.5 to 5.0.

In the present composition, the higher alkenyl group in the component (a) is preferably hexenyl, and the content of the hexenyl group in the component (a) is preferably 0.5 to 3.0 mass% in terms of vinyl group (CH ₂ =ch-).

In the present composition, it is preferable that both ends of the molecular chain of the component (B) are blocked with trialkylsiloxy groups.

The composition is suitable for forming a release cured coating.

The laminate of the present invention is characterized by comprising a cured product layer obtained by curing the curable organopolysiloxane composition on at least one surface of a sheet-like substrate.

The laminate of the present invention is characterized in that at least one surface of the sheet-like substrate has a release layer obtained by curing the curable organopolysiloxane composition, and the release layer has an adhesive layer thereon.

ADVANTAGEOUS EFFECTS OF INVENTION

The curable organopolysiloxane composition of the present invention has the feature that a cured film with stable peeling properties can be formed without impairing the adhesive properties of the adhesive substance. The laminate of the present invention has a characteristic of stable peeling performance.

Detailed Description

< Definition of terms >

The term "viscosity" as used in the present specification means a value (unit: mPas or Pa.s) at 25℃measured by a type B rotary viscometer in accordance with JIS K7117-1:1999 "plastic-resin in liquid, opaque or dispersed form-method of measuring apparent viscosity by a Brookfield rotary viscometer".

The term "side chain of a molecular chain" as used herein means a bonding position other than the end of a molecular chain, and "having an alkenyl group in a side chain of a molecular chain" means that an alkenyl group is bonded to a silicon atom other than the end of a molecular chain of a linear organopolysiloxane.

The term "content of vinyl groups (CH ₂ =ch-) as used herein refers to the content of vinyl groups when the alkenyl groups are converted to equimolar vinyl groups.

First, the curable organopolysiloxane of the present invention will be described in detail.

[ Component (A) ]

The component (A) is a linear organopolysiloxane having a higher alkenyl group having 4 to 12 carbon atoms at the terminal and side chain of the molecular chain. As the higher alkenyl group in the component (A), butenyl, pentenyl, hexenyl, heptenyl, octenyl, preferably hexenyl groups are exemplified. Examples of the silicon atom-bonded group other than the higher alkenyl group in the component (A) include an alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an aryl group having 6 to 12 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, an aralkyl group having 7 to 12 carbon atoms such as a benzyl group and a phenethyl group, a 3, 3-trifluoropropyl group, 4,4,4,3,3-pentafluorobutyl group, a 5,4, 3-heptafluoropentyl group, 6,6,6,5,5,4,4,3,3-nonafluorohexyl group, a 7,7,7,6,6,5,5,4,4,3,3-undecylfluoroheptyl group, and a fluorinated alkyl group having 3 to 12 carbon atoms such as a methyl group. In the component (A), an alkoxy group having 1 to 3 carbon atoms such as a hydroxyl group, a methoxy group, an ethoxy group or the like may be bonded to a silicon atom in a small amount within a range not to impair the object of the present invention.

The content of the higher alkenyl group in the component (a) is not limited, but in the case where the higher alkenyl group is hexenyl, the content of the hexenyl group in the component (a) in terms of vinyl group (CH ₂ =ch-) is preferably in the range of 0.5 to 3.0 mass%, or in the range of 0.5 to 2.0 mass%. This is because, if the content of the hexenyl group of the component (a) is not less than the lower limit of the above range, the present composition is sufficiently cured, migration of the silicone component to the adhesive substance of the obtained release cured film is suppressed, and the decrease in the residual adhesive rate of the adhesive substance can be suppressed, whereas if the content of the hexenyl group of the component (a) is not more than the upper limit of the above range, the obtained release cured film has a moderately light release resistance.

The viscosity of component (A) at 25 ℃ is in the range of 20 to 1500 mPas, preferably in the range of 50 to 1500 mPas, in the range of 50 to 1000 mPas, or in the range of 100 to 500 mPas. This is because, if the viscosity of the component (a) is equal to or higher than the lower limit of the above range, the curability of the present composition can be improved, while if the viscosity of the component (a) is equal to or lower than the upper limit of the above range, the resulting release cured film has a relatively light release resistance and little change with time.

Examples of the component (A) include a dimethylsiloxane-methylhexenyl siloxane copolymer terminated by dimethylsiloxane groups at both ends of the molecular chain and a methylhexenyl polysiloxane terminated by dimethylsiloxane groups at both ends of the molecular chain.

[ Component (B) ]

The component (B) is a linear organopolysiloxane having at least two alkenyl groups having 2 to 12 carbon atoms in the molecule only in the side chains of the molecular chain. Examples of the alkenyl group in the component (B) include vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl and octenyl groups, and vinyl groups are preferable. Examples of the group bonded to a silicon atom other than the alkenyl group in the component (B) include an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, and a fluoroalkyl group having 3 to 12 carbon atoms, which are exemplified as the component (A), and methyl groups are preferable. The component (B) has an alkenyl group only in a side chain of a molecular chain, but a group at a terminal of the molecular chain is not limited, and for example, a trialkylsilyl group is preferable. Examples of the trialkylsilyl group include trimethylsilyl and triethylsilyl. In the component (B), an alkoxy group having 1 to 3 carbon atoms such as a hydroxyl group, a methoxy group, an ethoxy group or the like may be bonded to a silicon atom in a small amount within a range not to impair the object of the present invention.

The content of the alkenyl group (CH ₂ =ch-) in terms of vinyl group is in the range of 0.1 to 0.3 mass%, preferably in the range of 0.1 to 0.25 mass%, or in the range of 0.1 to 0.2 mass% relative to the content of the alkenyl group of the component (B). This is because, if the content of the alkenyl group of the component (B) is not less than the lower limit of the above range, the present composition is sufficiently cured, migration of the silicone component to the adhesive substance of the obtained release cured film is suppressed, and the decrease in the residual adhesive rate of the adhesive substance can be suppressed, whereas if the content of the alkenyl group of the component (B) is not more than the upper limit of the above range, the obtained release cured film has a moderately light release resistance, and the change in release resistance due to the presence or absence of press treatment is small.

The viscosity of component (B) at 25℃is in the range of 3000 to 50000 mPas, preferably 4000 to 45000 mPas. This is because, if the viscosity of the component (B) is equal to or higher than the lower limit of the above range, the curability of the present composition can be improved, and if the viscosity of the component (B) is equal to or lower than the upper limit of the above range, the resulting release cured film has a relatively light release resistance, and the change in release resistance due to the presence or absence of press treatment is small. In particular, when the viscosity of the component (B) is low, the molecular weight thereof becomes low, and therefore the number of alkenyl groups in one molecule becomes small even if the alkenyl group content is the same. As a result, the reactivity of the component (B) becomes low, and migration of the silicone component to the adhesive substance of the release cured film is likely to occur. In order to suppress this, it is preferable to have a higher alkenyl group content. On the other hand, when the viscosity is high, the molecular weight becomes high, and therefore the number of alkenyl groups in one molecule becomes large even with the same alkenyl group content. As a result, the reactivity of the component (B) increases, and the silicone component tends to stay in the interior of the release cured film. In order to promote the local presence of the component (B) on the surface, it is effective to make a difference in the relative reactivity with the component (A), and it is preferable that the content of alkenyl groups therein is low.

Examples of the component (B) include a trimethylsiloxy-terminated dimethylsiloxane-methylvinylsiloxane copolymer at both ends of the molecular chain, a trimethylsiloxy-terminated methylvinylpolysiloxane at both ends of the molecular chain, and a dimethylhydroxysiloxy-terminated dimethylsiloxane-methylvinylsiloxane copolymer at both ends of the molecular chain.

In the present composition, the mass ratio { component (A)/component (B) } of the component (A) to the component (B) is in the range of 90/10 to 75/25, preferably in the range of 90/10 to 77/23. This is because, if the mass ratio is equal to or more than the lower limit of the above range, the curability of the present composition, particularly the curability at a low temperature of about 100 ℃, can be improved, and the strength of the resulting peel-off cured film can be improved, while if the mass ratio is equal to or less than the upper limit of the above range, the resulting peel-off cured film can have a relatively light peel resistance. In the present composition, component (B) is blended in a specific ratio to component (A), so that a releasable cured film having a relatively light release resistance, little change in release resistance due to the presence or absence of press treatment, and a reduction in residual adhesion rate of an adhesive substance can be suppressed can be formed.

[ Component (C) ]

Component (C) is an organohydrogen polysiloxane having at least two silicon atoms bonded to a hydrogen atom in one molecule. Examples of the group bonded to a silicon atom other than a hydrogen atom in the component (C) include an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, and a fluoroalkyl group having 3 to 12 carbon atoms, which are exemplified as the component (A), and methyl is preferable. In the component (C), an alkoxy group having 1 to 3 carbon atoms such as a hydroxyl group, a methoxy group, an ethoxy group, etc. may be bonded to a silicon atom in a small amount within a range that does not impair the object of the present invention.

The viscosity of component (C) at 25℃is not limited, but is preferably in the range of 1 to 1000 mPas, or in the range of 5 to 500 mPas. This is because, if the viscosity of the component (C) is not less than the lower limit of the above range, volatilization of the component (C) from the present composition is suppressed, and the composition is stable, whereas if the viscosity of the component (C) is not more than the upper limit of the above range, curability of the present composition is promoted.

The molecular structure of the component (C) is not limited, and examples thereof include linear, linear having a partial branch, branched, cyclic, and resin. Examples of the component (C) include a dimethylsiloxy-terminated dimethylsiloxane-methylhydrosiloxane copolymer having both ends of the molecular chain, a dimethylsiloxy-terminated dimethylpolysiloxane having both ends of the molecular chain, a trimethylsiloxy-terminated methylhydrosiloxane having both ends of the molecular chain, a cyclic methylhydrosiloxane-dimethylsiloxane copolymer, a copolymer of a siloxane unit represented by the formula H (CH ₃)₂SiO_1/2) and a siloxane unit represented by the formula SiO _4/2, and a copolymer of a siloxane unit represented by the formula (CH ₃)₃SiO_1/2) and a siloxane unit represented by the formula H (CH ₃)₂SiO_1/2) and a siloxane unit represented by the formula SiO _4/2.

In the present composition, the content of the component (C) is an amount in the range of 0.5 to 5.0, preferably in the range of 0.5 to 3.0, or in the range of 1.0 to 3.0, based on 1 mol of the sum of the higher alkenyl groups in the component (A) and the alkenyl groups in the component (B). This is because, if the content of the component (C) is not less than the lower limit of the above range, the curability of the present composition is improved, and if the content of the component (C) is not more than the upper limit of the above range, the resulting peeled cured film becomes slightly peeled from the adhesive substance.

[ Component (D) ]

Component (D) is a hydrosilylation catalyst for promoting the curing reaction of the present composition. The component (D) may be a platinum-based catalyst, a palladium-based catalyst, or a rhodium-based catalyst, and is preferably a platinum-based catalyst. The platinum-based catalyst is a catalyst containing a platinum-based metal, and specifically, examples thereof include chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, complexes of chloroplatinic acid and ketones, complexes of chloroplatinic acid and vinyl siloxane, platinum tetrachloride, platinum fine powder, a solid platinum supported on alumina or silica carrier, platinum black, olefin complexes of platinum, alkenyl siloxane complexes of platinum, carbonyl complexes of platinum, and platinum-based catalyst of thermoplastic organic resin powder such as methyl methacrylate resin, polycarbonate resin, polystyrene resin, and silicone resin containing these platinum-based catalysts. In particular, platinum-based siloxane complexes such as a complex of chloroplatinic acid and divinyl tetramethyl disiloxane, a complex of chloroplatinic acid and tetramethyl tetravinyl cyclotetrasiloxane, a platinum divinyl tetramethyl disiloxane complex, and a platinum tetramethyl tetravinyl cyclotetrasiloxane complex are preferable.

The content of the component (D) is an amount of a catalyst for promoting the hydrosilylation reaction of the present composition, specifically, an amount of a catalyst metal in the present component in a mass unit of 1 to 1000ppm or an amount in a range of 5 to 500ppm relative to the total amount of the components (A) to (C). This is because, if the content of the component (D) is not less than the lower limit of the above range, the curing of the present composition is promoted, whereas if the content of the component (D) is not more than the upper limit of the above range, the resulting release cured film is less likely to suffer from problems such as coloration.

The present composition may contain a hydrosilylation reaction inhibitor (E) for adjusting the curing rate. Examples of the component (E) include silanized ethinyl alcohols such as 2-methyl-3-butyn-2-ol, 3, 5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentyn-3-ol, 2-phenyl-3-butyn-2-ol, 1-ethynyl-1-cyclohexanol, 2-ethynyl isopropanol, and 2-ethynyl butane-2-ol, alkynols such as trimethyl (3, 5-dimethyl-1-hexyn-3-oxy) silane, dimethyl bis (3-methyl-1-butynyloxy) silane, methyl vinyl bis (3-methyl-1-butyn-3-oxy) silane, [ (1, 1-dimethyl-2-propynyloxy ] trimethylsilane), silanized ethinyl alcohols such as 2-isobutyl-1-butene-3-yne, 3, 5-dimethyl-3-hexene-1-yne, 3-methyl-3-pentene-1-yne, 3-methyl-3-hexene-1-yne, 3-methyl-1-hexene-cyclohexene, 1-ethyl-3-butene-3-yne, and diethyl fumarate, and the like, unsaturated carboxylic acid esters such as bis-2-methoxy-1-methylethyl maleate, monooctyl maleate, monoisooctyl maleate, monoallyl maleate, monomethyl maleate, monoethyl fumarate, monoallyl fumarate, and 2-methoxy-1-methylethyl maleate, alkenylsiloxanes such as 1,3,5, 7-tetramethyl-1, 3,5, 7-tetravinylcyclotetrasiloxane, 1,3,5, 7-tetramethyl-1, 3,5, 7-tetrahexenylmethylsiloxane, and benzotriazole.

In the present composition, the content of the component (E) is not limited, but is preferably 0.001 parts by mass or more, 0.01 parts by mass or more, or 0.1 parts by mass or more, and on the other hand, 5 parts by mass or less, or 3 parts by mass or less, based on 100 parts by mass of the total of the component (a) and the component (B).

The composition can be used under substantially solvent-free conditions, or can be diluted with a known organic solvent. Examples of the organic solvent include aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane, octane and isoparaffin, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate and isobutyl acetate, ether solvents such as diisopropyl ether and 1, 4-dioxane, cyclic polysiloxanes having a polymerization degree of 3 to 6 such as hexamethylcyclotrisiloxane, octamethyltetrasiloxane and decamethylcyclopentasiloxane, and halogenated hydrocarbons such as trichloroethylene, perchloroethylene, trifluoromethylbenzene, 1, 3-bis (trifluoromethyl) benzene and methyl pentafluorophenyl. In particular, when a sheet-like substrate such as polyolefin having low heat resistance is thinly coated, an ether solvent is preferable from the viewpoints of curability and swelling property.

The composition may contain, as optional components, an adhesion promoter comprising an alkoxysilane compound such as 3-glycidoxypropyl trimethoxysilane or 3-methacryloxypropyl trimethoxysilane, an antioxidant such as a phenol, quinone, amine, phosphorus, phosphate, sulfur, thioether, a light stabilizer such as triazole, benzophenone, a flame retardant such as phosphate, halogen, phosphorus, antimony, one or more antistatic agents including a cationic surfactant, an anionic surfactant, a nonionic surfactant, and other known additives such as a heat stabilizer, a dye, and a pigment.

Further, since the obtained cured film is excellent in physical properties and releasability, the present composition can be cured by irradiation with energy rays (also referred to as chemical action rays), for example, ultraviolet rays or electron rays, particularly ultraviolet rays. In this case, the curing with ultraviolet rays includes curing with ultraviolet rays only or curing with ultraviolet rays and heat. In order to impart good ultraviolet curability to the present composition, a photopolymerization initiator (F) may be further included. The component (F) is a component which imparts ultraviolet curability to the present composition, and has advantages in that damage to a plastic film substrate having low heat resistance due to heat is reduced by using both heat curing by an addition reaction and ultraviolet curing, and in that adhesion of a cured product obtained by curing the present composition to a plastic film is improved. Further, there is an advantage that transfer of the silicone component from the surface of the cured film obtained by curing the present composition onto the sheet can be prevented, and the sheet is contaminated with the silicone component (this is referred to as the transfer property of silicone), and the transfer property of silicone is further reduced.

The component (F) can be suitably selected from among those known as compounds which generate radicals by irradiation with ultraviolet rays, for example, organic peroxides, carbonyl compounds, organic sulfur compounds, azo compounds, etc., and specifically, acetophenone, propiophenone, benzophenone, xanthene alcohol (xanthol), fluorene, benzaldehyde, anthraquinone, triphenylamine, 4-methylacetophenone, 3-pentylacetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-allylacetophenone, p-diacetylbenzene, 3-methoxybenzophenone, 4-methylbenzophenone, 4-chlorobenzophenone, 4-dimethoxybenzophenone, 4-chloro-4-benzylbenzophenone, 3-chloroxanthone, 3, 9-dichloroxanthone, 3-chloro-8-nonyloxyxanthone, benzoin methyl ether, benzoin butyl ether, bis (4-dimethylaminophenyl) ketone, benzylmethoxy, 2-chlorothioxanthone, diethyl, 2-methyl [4- (methylthiophenyl ] 2-cyclohexyl) ketone, 2-cyclohexyl-2-hydroxy-acetophenone, and the like, and, particularly, as a mixture thereof, preferable examples are given above.

The content of the component (F) is not limited, but is preferably in the range of 0.01 to 10 parts by mass, or in the range of 0.01 to 2.5 parts by mass, relative to 100 parts by mass of the component (A). When the content of the component (F) is within the above range, the transferability of the silicone of the release cured film obtained by curing the present composition can be improved, and physical properties such as mechanical strength can be improved.

[ Method for producing the composition ]

The composition can be prepared by simply and uniformly mixing the above components (A) to (D), and further component (E), and any other components. The order of addition of the components is not particularly limited, but when the components are not used immediately after mixing, it is preferable to store the component (a), the component (B), and the component (C) separately in advance and mix them immediately before use. In addition, in the composition including the components (a) to (D) and the component (E), by adjusting the content of the component (E), a composition which is not crosslinked at normal temperature and which is crosslinked and cured upon heating can be produced.

When the composition is uniformly applied to a sheet-like substrate and heated under conditions sufficient for the hydrosilylation reaction of the component (A) and the component (C) to crosslink, a sheet-like substrate having a cured layer excellent in slidability, transparency and adhesion to the sheet-like substrate on the surface of the sheet-like substrate can be produced. The cured layer obtained by curing the composition has the advantage of excellent flexibility and air permeability, and less air bubbles are involved even when the composition is attached to a non-planar object. Therefore, the cured film is very preferably used for applications such as optical displays and protective films on glass surfaces, in which both the peeling property of the cured layer and the adhesion property of the cured layer to the object to be protected are paid attention to.

Next, the laminate of the present invention will be described in detail.

The laminate is characterized by having a cured product layer obtained by curing the composition on at least one surface of a sheet-like substrate.

The laminate is not limited, and examples of the sheet-like substrate include a sheet-like substrate made of polyester such as polyethylene terephthalate and polyethylene naphthalate, polyolefin such as polypropylene and polymethylpentene, polycarbonate, polyimide, a film made of plastic such as polyvinyl acetate, paper such as paper, cardboard, corrugated paper, cellophane, clay coated paper, polyolefin laminated paper, polyethylene laminated paper and synthetic paper, cloth such as natural fiber cloth, synthetic fiber cloth and artificial leather cloth, and glass wool and metal foil. The film may be a single layer or may be composed of two or more layers containing plastics of the same kind or different kinds. The substrate is preferably a plastic film, particularly preferably a polyester film, further preferably a polyethylene terephthalate film, and particularly preferably a biaxially stretched polyethylene terephthalate film. The polyethylene terephthalate film is less prone to dust generation during processing, use, and the like. Therefore, the coating failure of the adhesive substance due to dust or the like on the release sheet can be effectively prevented. Further, the antistatic treatment is performed on the polyethylene terephthalate film, and the antistatic treatment is used as a base material, whereby occurrence of coating failure or the like of an adhesive substance can be prevented.

The thickness of the sheet-like substrate is not particularly limited, but is usually 10 to 300. Mu.m, preferably 15 to 200. Mu.m, particularly preferably 20 to 125. Mu.m.

Further, in order to improve the adhesion between the sheet-like substrate and the cured layer, a support film subjected to a primer treatment, a corona treatment, an etching treatment, or a plasma treatment may be used. Examples of usable primer compositions include condensation-type silicone primer compositions containing diorganopolysiloxanes having SiOH groups at the terminal, polysiloxanes having SiH groups and/or polysiloxanes having alkoxy groups, and condensation reaction catalysts, and addition-type silicone primer compositions containing diorganopolysiloxanes having alkenyl groups such as vinyl groups, polysiloxanes having SiH groups, and addition reaction catalysts.

Further, the surface of the sheet-like substrate opposite to the cured layer may be subjected to surface treatments such as scratch prevention, stain prevention, fingerprint adhesion prevention, antiglare, antireflection, and antistatic. The sheet-like substrate may be coated with the composition and then subjected to the surface treatment described above, or may be coated with the composition after the surface treatment has been performed in advance. Examples of the scratch preventing treatment (hard coat treatment) include treatment with a hard coat agent such as an acrylic acid ester-based, silicone-based, oxetane-based, inorganic-based, or organic-inorganic hybrid-based. Examples of the anti-fouling treatment include treatment with an anti-fouling treatment agent such as fluorine-based, silicone-based, ceramic-based, or photocatalyst-based. Examples of the anti-reflection treatment include wet treatment by application of an anti-reflection agent such as fluorine-based or silicone-based, and dry treatment by vapor deposition or sputtering. Examples of antistatic treatment include treatment with antistatic agents such as surfactants, silicones, organoboranes, conductive polymers, metal oxides, and vapor deposited metals.

The temperature for curing the present composition on the sheet-like substrate is usually 50 to 200 ℃. The heating method is not particularly limited, and examples thereof include heating in a hot air circulation oven, passing through a long heating furnace, and radiating heat by an infrared lamp or a halogen lamp. In addition, it may be cured by a combination of heat and ultraviolet irradiation. When the component (D) is a platinum-based siloxane complex catalyst, a cured layer excellent in slidability, transparency and adhesion to a sheet-like substrate can be easily obtained in a short time of 1 to 40 seconds at 100 to 150 ℃ even if the amount of the platinum-based siloxane complex catalyst is 1 to 5000ppm in terms of the platinum metal amount relative to the total amount of the composition.

On the other hand, for a sheet-like substrate of polyolefin or the like having low heat resistance, it is preferable to apply the present composition to the sheet-like substrate of polyolefin or the like and then heat it at a low temperature of 50 to 100 ℃, more preferably 50 to 80 ℃. In this case, the curing time is 30 seconds to several minutes (for example, 1 to 10 minutes), and stable curing is possible.

As a method of applying the present composition to a sheet-like substrate, dipping, spraying, gravure coating (gravure coat), offset coating (offset coat), indirect gravure coating (offset coat), roll coating using a rubber roll transfer roll coater (offset rotogravure roll coater) or the like, reverse roll coating, air knife coating (air knife coat), curtain coating using a curtain coating flow coater (curtain flow coater) or the like, comma knife coating, mayer Bar (Mayer Bar), and other well-known methods for forming a cured layer can be used without limitation. The thickness of the releasable cured film on the substrate is not limited, but is preferably in the range of 0.01 to 3 μm or in the range of 0.03 to 2 μm. This is because, if the thickness of the releasable cured film is equal to or greater than the lower limit of the above range, the adhesive substance is likely to be released, while if the thickness of the releasable cured film is equal to or less than the upper limit of the above range, the occurrence of blocking can be suppressed when the obtained release sheet is wound into a roll.

The composition is useful for forming a cured layer excellent in surface slidability and releasability from an adhesive substance, and is particularly suitable as a release cured film forming agent for engineering paper, asphalt packaging paper, and various plastic films.

The laminate is characterized in that at least one surface of the sheet-like substrate has a release layer obtained by curing the composition, and the release layer has an adhesive layer thereon.

In particular, since the release layer obtained by curing the composition is excellent in release properties with respect to other adhesive layers, the release layer can be used as a release layer for a laminate such as a laminate including an adhesive layer, an engineering paper, an adhesive material wrapping paper, an adhesive tape, and an adhesive label. Specifically, by using the present composition, a laminate can be obtained which is formed by attaching an adhesive sheet having an adhesive layer (or an adhesive layer) on at least one surface of a sheet-like substrate to a sheet-like substrate such that the adhesive layer is in contact with the cured layer, wherein the sheet-like substrate has a cured layer (release layer or release layer) formed by heat curing the present composition on at least one surface of the sheet-like substrate.

Examples of the adhesive material suitable for the laminate include various adhesives, and the like, and examples thereof include acrylic adhesives, rubber adhesives, and silicone adhesives, acrylic adhesives, synthetic rubber adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives. Examples of the adhesive food such as asphalt and rice cake include paste and bird glue.

On the other hand, the cured layer formed from the present composition is extremely useful in that it can be used as an adhesive layer having micro-adhesiveness while having excellent peeling properties equivalent to those in the case of thin coating, particularly as an adhesive layer such as a protective sheet or a re-peeling adhesive sheet, by applying the composition to a thick layer. The adhesive layer has the advantages that the adhesive property to an object is stably maintained for a long time after the adhesion, and the adhesion position is not shifted or peeled off, but the peeling property after the long-time adhesion is excellent. In addition, the protective sheet has the advantages of easy re-adhesion, and difficult deformation, whitening, residual glue and the like of a cured layer when the protective sheet is used for a long time.

The protective sheet or the removable adhesive sheet having a cured layer formed from the composition of the present invention is used for the purpose of adhering and protecting the surface of a member such as a metal plate, a coated metal plate, an aluminum window frame, a plastic plate, a decorative plate, a polyvinyl chloride laminate, or a glass plate when the member is transported, processed, or cured. The protective sheet can be suitably used for a process for manufacturing various liquid crystal display panels (also referred to as monitors or displays), a process for distributing polarizing plates, a process for manufacturing various resin members for machines such as automobiles, a process for distributing resin members, food packaging, and the like.

Similarly, the protective sheet having an adhesive layer formed of a cured layer of the present composition is easily reattached, and therefore is suitable for various protective sheets for displays as follows. The protective film of the present invention is used for the purpose of preventing injury, stain, fingerprint adhesion, electrification, reflection, peeping, etc. on the surface in various cases when these displays are manufactured, circulated, and used.

The laminate of the surface protective sheet can be obtained, specifically, by using the present composition, and by attaching a release sheet having a release layer on at least one surface of a sheet-like substrate to a sheet-like substrate, wherein the release layer is in contact with the cured layer, on the sheet-like substrate having a cured layer (release layer and adhesive layer) formed by heat curing the present composition on at least one surface of the sheet-like substrate.

Examples

The curable organopolysiloxane composition and laminate of the present invention are described in further detail by examples. The present invention is not limited to these examples. Further, the viscosity in the examples is a value of 25℃measured using a Brookfield (Brookfield) model DV1 rotational viscometer manufactured by Brookfield company, which is "a plastic-liquid, opaque or dispersible resin-a measurement method of apparent viscosity by Brookfield rotational viscometer" according to JIS K7117-1:1999.

The release sheet was produced and evaluated as follows.

< Method for producing Release sheet >

The curable organopolysiloxane composition was applied to the surface of a substrate in such a manner that the silicone content was 0.6g/m ², using a printing suitability tester (manufactured by Ming, ltd.; RI-2). After the coating, the coated film was subjected to heat treatment in a hot air circulation oven at 120 ℃ for 30 seconds, thereby producing a release sheet having a release cured film on the surface of the substrate.

< Aging of Release sheet (stamping treatment) >)

A part of the release sheet produced by the above method was left to stand under no load at 23 ℃ and 65% rh, and was used as an "untreated release sheet". The other release sheet was subjected to a press treatment at 23℃and 65% RH for 20 hours under a pressure of 20g/cm ², to obtain a "press-treated release sheet".

< Peel resistance of adhesive substance >

An acrylic adhesive (trade name Oribain BPS5127, manufactured by TOYOBO INJECT Co., ltd.) was uniformly applied to the surface of the release cured film so that the wet thickness was 70. Mu.m, using an applicator, and dried at 70℃for 2 minutes. Then, after double-sided art coated paper (manufactured by Xiaolin Co., ltd.) was attached thereto, a load of 20g/cm ² was applied, and the resultant was left to stand at 25℃and 60% humidity for 1 day. Then, the peeling force when the bonded paper was stretched at a speed of 0.3 m/min in the 180 ° direction was measured using a tensile tester. In addition, the peel force is required to be 150mN/50mm or less in both the untreated release sheet and the press-treated release sheet.

< Heavy Peel conversion ratio >

The re-peeling rate was calculated by measuring the peeling resistance between the press-processed sample and the untreated sample during the aging, and the following formula was used.

Heavy peeling rate= (peeling resistance of press-treated peel sheet/peeling resistance of untreated peel sheet)

The re-peeling rate is required to be 1.10 or less.

< Residual adhesion Rate >

A tape No.31B manufactured by Nito electric company was attached to the release sheet, and the sheet was left to stand at a temperature of 70℃for 20 hours under a load of 20g/cm ². Then, the tape was peeled off, attached to a stainless steel plate, placed under a load of 20g/cm ² in air at 25℃and 60% humidity for 30 minutes, and then stretched under conditions of 180 degrees and a peeling speed of 0.3m/min by a tensile tester [ TENSILON Universal tester manufactured by Kagaku Co., ltd. ], to measure a force (gf 1) required for peeling. As a blank test, the adhesive tape was attached to a teflon (registered trademark) sheet in the same manner as described above, and the force (gf 2) required for peeling off the adhesive tape was measured in the same manner as described above. From these values, the residual adhesion (%) was calculated according to the following formula.

Residual adhesion (%) = (gf 1/gf 2) ×100

The residual adhesion rate is required to be 90% or more.

< Examples 1 to 6, comparative examples 1 to 19>

The following components were uniformly mixed so as to have the compositions shown in tables 1 to 4, to prepare curable organopolysiloxane compositions. In the table, the content of the component (D) is an amount of 100ppm by mass of platinum in the component (D) relative to the total amount of the components (a) to (C). In the table, "component (a)/component (B)" represents a ratio of the content of component (a) to the content of component (B), and "SiH/CH ₂ =ch" represents a ratio of the number of moles of silicon atom-bonded hydrogen atoms in component (C) to the number of moles of alkenyl groups in the total of component (a) and component (B). The properties of the release sheet produced using the curable organopolysiloxane composition thus prepared were measured, and the results are shown in tables 1 to 4.

As component (a), the following components were used.

(A-1) A dimethylsiloxane-methylhexenyl siloxane copolymer having a viscosity of 200 mPas and having both molecular chain ends terminated with dimethylhexenyl siloxane groups (content of hexenyl groups converted to vinyl groups=1.15 mass%).

In order to compare component (a), the following components were used.

(A-2) dimethylsiloxane-methylhexenyl siloxane copolymer having a viscosity of 200 mPas and having both molecular chain ends terminated with dimethylvinylsiloxy groups (content of vinyl groups and hexenyl groups converted to vinyl groups=1.10 mass%)

(A-3) dimethylsiloxane-methylvinylsiloxane copolymer having a viscosity of 350 mPas and having both molecular chain ends terminated by methylvinylsiloxy groups (vinyl content=0.94% by mass)

(A-4) dimethylsiloxane-methylhexenyl siloxane copolymer having a viscosity of 350 mPas and having both ends of the molecular chain terminated by trimethylsiloxy groups (content of hexenyl groups converted to vinyl groups=1.25 mass%)

As component (B), the following components were used.

(B-1) dimethylsiloxane-methylvinylsiloxane copolymer having a viscosity of 5000 mPas and having both ends of the molecular chain terminated by trimethylsiloxy groups (content of vinyl groups=0.15 mass%)

(B-2) Dimethylsiloxane-methylvinylsiloxane copolymer having a viscosity of 40000 mPas and having both ends of the molecular chain terminated by trimethylsiloxy groups (content of vinyl group=0.15 mass%)

In order to compare component (B), the following components were used.

(B-3) dimethylsiloxane-methylvinylsiloxane copolymer having a viscosity of 35000 mPas and having both ends of the molecular chain terminated with trimethylsiloxy groups (content of vinyl groups=0.5% by mass)

(B-4) dimethylsiloxane-methylvinylsiloxane copolymer having a viscosity of 8000 mPas and having both ends of the molecular chain terminated by trimethylsiloxy groups (content of vinyl groups=0.31% by mass)

(B-5) dimethylpolysiloxane having a viscosity of 350 mPas and having both molecular chain ends terminated with trimethylsiloxy groups

(B-6) dimethylpolysiloxane having a viscosity of 5000 mPas and having both molecular chain ends terminated with trimethylsiloxy groups

(B-7) dimethylpolysiloxane having a viscosity of 10000 mPas and having both molecular chain ends terminated with trimethylsiloxy groups

(B-8) dimethylpolysiloxane having a viscosity of 2300 mPas and having both molecular chain ends terminated with dimethylhydroxysiloxy groups

(B-9) dimethylpolysiloxane having a viscosity of 13500 mPas and having both molecular chain ends terminated with dimethylhydroxysiloxy groups

(B-10) dimethylpolysiloxane having a viscosity of 4000 mPas and having both molecular chain ends terminated with dimethylhydroxysiloxy groups

(B-11) dimethylpolysiloxane having a viscosity of 2000 mPas and having both molecular chain ends terminated by dimethylvinylsiloxy groups (vinyl content=0.23% by mass)

(B-12) dimethylpolysiloxane having a viscosity of 10000 mPas and a molecular chain end-capped with dimethylvinyl groups (vinyl group content=0.13 mass%)

As the component (C), the following components were used.

(C-1) methyl hydrogen polysiloxane having a viscosity of 20 mPas and having both ends of the molecular chain terminated by trimethylsiloxy groups (content of silicon atom-bonded hydrogen atom=1.58% by mass)

As component (D), the following components were used.

(D-1) 1, 3-Divinyltetramethyldisiloxane solution of 1, 3-Divinyltetramethyldisiloxane Complex of platinum (platinum content 6500 ppm)

As component (E), the following components were used.

(E-1) 1-ethynyl-cyclohexane-1-ol

TABLE 1

TABLE 2

TABLE 3

TABLE 4

From the results shown in tables 1 to 4, when a dimethylsiloxane-methylvinylsiloxane copolymer having both ends of the molecular chain blocked with trimethylsiloxy groups and having a vinyl group content of more than 0.3 mass% was used as the component (B) (comparative examples 1 and 2), the peeling resistance after the press treatment became heavy, that is, heavy peeling occurred. It was found that even when a dimethylsiloxane-methylvinylsiloxane copolymer having a vinyl group content of 0.3 mass% or less and having both ends of the molecular chain blocked with trimethylsiloxy groups was used as the component (B), it was difficult to sufficiently and lightly peel the component (a)/component (B) out of the range of 90/10 to 75/25 (comparative examples 14 and 17), and that the residual adhesive ratio was significantly reduced (comparative examples 15, 16, 18 and 19). Further, it was found that, when dimethylpolysiloxane having trimethylsilyl groups at both ends of the molecular chain (comparative examples 3 to 5) and dimethylpolysiloxane having dimethylsilanol groups at both ends of the molecular chain (comparative examples 6 to 8) were used as the component (B), the tendency of re-peeling was large and the residual adhesion was significantly reduced. In addition, it was found that when a dimethylsiloxane-methylvinylsiloxane copolymer having a vinyl group content of 0.3 mass% or less and both molecular chain ends end-capped with dimethylvinyl groups was used as the component (B) (comparative examples 9 and 10), the re-peeling rate and the residual adhesion rate were good, but the peeling resistance became heavy. In addition, it was found that when a dimethylsiloxane-methylhexenyl siloxane copolymer having hexenyl groups only in the side chains of the molecular chain was used as the component (a) (comparative example 13), the tendency of heavy peeling was large and the residual adhesion rate was low.

On the other hand, in the present application (examples 1 to 6), the peeling resistance was small, the re-peeling rate was low when the cured release sheet was subjected to press treatment, and the residual adhesion rate was not lowered.

Industrial applicability

The curable organopolysiloxane composition of the present invention can form a cured film with stable release properties without impairing the adhesive properties of the adhesive substance, and is therefore suitable as a composition for forming a release cured film. That is, even when a release sheet obtained by applying and curing a release sheet coated on a sheet-like substrate such as a polyethylene laminated paper is laminated and subjected to a press treatment, the composition has a small difference in peeling between a release layer formed from the composition and a release layer which is not subjected to a press treatment, has stable peeling performance, and can suppress the decrease in adhesiveness of the adhesive substance, so that a laminate comprising a release layer using the composition and an adhesive layer such as a release tape/sheet can be provided.

Claims

1. A curable organopolysiloxane composition comprising a base and a curable organopolysiloxane, it comprises:

A linear organopolysiloxane (B) having a viscosity of 3000 to 50000 mPa.s at 25 ℃ and having at least two alkenyl groups having 2 to 12 carbon atoms in one molecule only in side chains of a molecular chain, wherein the alkenyl groups in the component (B) are contained in an amount of 0.1 to 0.3 mass% in terms of vinyl groups CH ₂ = CH-;

A catalytic amount of a hydrosilylation catalyst (D),

2. The curable organopolysiloxane composition according to claim 1, wherein the higher alkenyl group in component (a) is hexenyl, and the content of hexenyl in component (a) is 0.5 to 3.0 mass% in terms of vinyl CH ₂ = CH-.

3. The curable organopolysiloxane composition according to claim 1 or claim 2, wherein both ends of a molecular chain of component (B) are blocked with trialkylsiloxy groups.

4. The curable organopolysiloxane composition according to claim 1 or claim 2, for forming a release curable coating film.

5. The curable organopolysiloxane composition according to claim 3, which is used for forming a release curable coating film.

6. A laminate comprising a sheet-like substrate and, on at least one surface thereof, a cured layer obtained by curing the curable organopolysiloxane composition according to claim 1 or claim 2.

7. A laminate comprising a sheet-like substrate and, on at least one surface thereof, a cured product layer obtained by curing the curable organopolysiloxane composition according to claim 3.

8. A laminate comprising a release layer obtained by curing the curable organopolysiloxane composition according to claim 1 or claim 2 on at least one surface of a sheet-like substrate, and an adhesive layer on the release layer.

9. A laminate comprising a release layer obtained by curing the curable organopolysiloxane composition according to claim 3 on at least one surface of a sheet-like substrate, and an adhesive layer on the release layer.