JP3420859B2 - Release Sheet Manufacturing Method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a release sheet.

[0002]

2. Description of the Related Art A pressure sensitive adhesive tape or pressure sensitive adhesive sheet is provided with a protective sheet for protecting the pressure sensitive adhesive surface thereof until it is finally used. Since the protective sheet must be finally peeled off, the adhesive force between the adhesive surface and the protective sheet must be light.

In order to achieve this, a protective sheet is provided with a releasable layer on the surface in contact with the pressure-sensitive adhesive with a release agent, and a protective sheet having a releasable layer provided on a base material. However, most of the products that are wrapped and stored like an adhesive tape do not use an independent material as a protective sheet, and an adhesive layer of the adhesive tape or the base material of the adhesive sheet is provided. A releasable layer is provided on the opposite surface (rear surface) using a release agent. The above-mentioned protective sheet including the base material whose back surface of the pressure-sensitive adhesive tape or sheet has been subjected to a release treatment is usually called a release sheet.

The release agent used in the release sheet includes
In addition to the releasability that reduces the peeling force when peeling the release sheet from the adhesive layer, the release agent layer does not cause cohesive failure to contaminate the adhesive and adversely affect the adhesiveness. Performance called migration is also required. As an example of the release agent having the above performance, a silicone-based release agent made of polyorganosiloxane, a release agent made of a substance such as a long-chain alkyl modified polyvinyl alcohol and a long-chain alkyl modified polyethyleneimine, and the like, Organic release agents are used. These release agents are used in the form of being applied on a substrate as a solution dissolved in an organic solvent and then dried to form a release layer.

However, in recent years, due to safety or environmental problems, there is a demand for a releasable layer forming method that does not use an organic solvent even in the production of a release sheet, that is, a so-called solvent-free method. As a method for forming a releasable layer of the above silicone-based release agent without solvent, it can be obtained by curing an organosiloxane oligomer with heat or radiation, but in the solventless method, it is suitable for coating with a solvent. Since the viscosity cannot be adjusted, there is a problem in the coating property that thin and uniform coating is performed, and further, there is a problem that the radiation irradiating device required for curing becomes large in size.

In view of the above problems, a water-dispersed release agent in which a release agent component is dispersed in water has been developed as a solvent-free method. For example, JP-A-3-86778 discloses that
An aqueous release agent using an aqueous dispersion obtained by post-emulsifying a long chain alkyl graft polymer obtained by reacting polyvinyl alcohol, polyallyl alcohol or a modified product thereof with an alkyl isocyanate is disclosed.

However, when an attempt is made to obtain a release sheet by using the aqueous release agent disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-86778, the release property and the non-release property are lower than those of the conventional solvent type release agents. After applying the above-mentioned aqueous release agent in order to express release performance such as transferability, it is necessary to heat for a long time and there is a problem that productivity of production of the release sheet is low.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above facts, and an object of the present invention is to provide a mold release capable of exhibiting excellent mold release performance in a short treatment time. A sheet manufacturing method is provided.

[0009]

According to the present invention of claim 1, a water-dispersed release agent composition dispersed in water is applied to a substrate and dried, and then the water-dispersed release agent is applied. A method for producing a release sheet, which comprises pressurizing a mold agent composition coated surface under heating to melt and smooth a release agent component,

According to the second aspect of the present invention, in the water-dispersed release agent composition, [1] (a) vinyl acetate having a degree of polymerization of 300 to 5,000 and a degree of saponification of 50 mol% or more. With respect to 1 equivalent of the hydroxyl group of the copolymer, (b) at least one functional group reactive with a hydroxyl group selected from the group consisting of an isocyanate group, a carboxyl group, an acid halide group, a ketene group, an aldehyde group and an epoxy group. And having 6 to 6 carbon atoms
0.5 for long-chain alkyl compounds having 30 alkyl groups
A component obtained by reacting in an equivalent ratio or more and [2] one or more kinds of fatty acids having 10 to 30 carbon atoms and / or an acid-modified polyolefin-based (co) polymer component having an acid value of 0.2 to 800 The method for producing a release sheet according to claim 1, wherein the release sheet is dispersed in water.

The water-dispersed release agent composition used in the present invention according to claim 1 is particularly limited as long as it is a so-called water-dispersed release agent in which the release agent component is dispersed in water. Examples thereof include, but are not limited to, silicone-based release agents made of polyorganosiloxane and organic release agents having long-chain alkyl groups. Since the above-mentioned release agent is mainly used for a release sheet temporarily attached for protection of the adhesive layer, the release agent for the thermoplastic resin used at the time of extrusion molding or injection molding of the thermoplastic resin. As described above, it melts during the above heat molding, does not exhibit releasability by causing cohesive failure and migrates, and is not a liquid at least under the conditions of being coated on a release sheet and used, Must be solid.

As the above silicone-based releasing agent, polyorganosiloxane is used in combination with other substances rather than being used alone. For example, it is copolymerized with polyalkylene oxide or introduced with a polyether group. Or a composition containing nitrocellulose, an alkyl ether-maleic anhydride copolymer, polyvinyl methyl ether, or the like.

Examples of the organic release agent having a long chain alkyl group include long chain alkyl acrylate copolymers, long chain alkyl vinyl ester copolymers, long chain alkyl acrylamide copolymers, and long chain alkyl derivatives of maleic acid. , Long-chain alkyl allyl ester copolymers, long-chain alkyl carbamates of carboxyl group-containing polymers such as ethylene-acrylic acid copolymers, long-chain alkyls of hydroxyl group-containing polymers such as polyvinyl alcohol and polyallyl alcohol Carbamate, long-chain alkyl modification of polyalkyleneimine, long-chain alkyl modification of polyallylamine,
Examples include long-chain alkyl modified polyamines. Grace
The long-chain alkyl group referred to here is an alkyl group having 6 to 30 carbon atoms.

The organic release agent is a polymer having a functional group such as a hydroxyl group and a compound having a reactive functional group and a long-chain alkyl group, for example, an esterification reaction, a urethanization reaction, and a urea conversion. It can be obtained by utilizing various reactions such as reaction, or by modifying a monomer having a long-chain alkyl group.

Among the above organic release agents, compared to silicone type release agents, characters and patterns can be drawn on the release-treated surface with magic ink or the like (drawability), and the release sheet. Adhesive tape can be further laminated on the release treated surface such as adhesive tape (overlapping property), so sealing can be done reliably, and it is difficult to slip between release treated surfaces (non-slip property) However, some of them have excellent performance such that the cargo is not easily collapsed even when the cardboard-packaged items are stacked in multiple stages such as during storage. Therefore, it is desirable to select and use them appropriately according to the application.

Among the above organic release agents, among others, [1]
(A) Hydroxyl group 1 of vinyl acetate copolymer having a degree of polymerization of 300 to 5000 and a degree of saponification of 50 mol% or more.
With respect to the equivalent weight, (b) has at least one functional group that reacts with a hydroxyl group selected from the group consisting of an isocyanate group, a carboxyl group, an acid halide group, a ketene group, an aldehyde group, and an epoxy group, and carbon A component obtained by reacting a long-chain alkyl compound having an alkyl group of 6 to 30 at a ratio of 0.5 equivalent or more, and [2] one or more kinds of fatty acids having 10 to 30 carbon atoms and / or an acid value of The water-dispersed release agent composition in which 0.2 to 800 acid-modified polyolefin-based (co) polymer components are dispersed in water is particularly excellent in releasability and non-migration property.

In the present invention according to claim 2, [1]
The vinyl acetate copolymer (a) is a copolymer mainly composed of vinyl acetate and a monomer copolymerizable therewith,
(A) Polymerization degree is 300 to 5000, preferably 800 to
It is 2,500 and the saponification degree is 50 mol% or more, preferably 60 mol% or more. The term "saponification degree" as used herein means the molar ratio (%) of the number of units of the saponified vinyl acetate moiety to the total number of units of the monomers constituting the vinyl acetate copolymer.

Examples of the monomer copolymerizable with vinyl acetate include ethylene and acrylic acid.

The vinyl acetate copolymer has a degree of polymerization of 300.
When the amount is less than the above, the releasing performance is deteriorated, and when the degree of polymerization exceeds 5,000, the water dispersibility of the releasing agent component is deteriorated, and both are not preferable. Further, when the saponification degree of the vinyl acetate copolymer is less than 50 mol%, the reactive hydroxyl groups are decreased and the releasing performance of the obtained releasing agent is deteriorated.

Further, (b) it has a functional group that reacts with one or more hydroxyl groups selected from the group consisting of an isocyanate group, a carboxyl group, an acid halide group, a ketene group, an aldehyde group and an epoxy group, and The long-chain alkyl compound having an alkyl group having 6 or more carbon atoms, preferably 8 or more is composed of the hydroxyl group of the vinyl acetate copolymer and the isocyanate group, carboxyl group, acid halide group, ketene group, aldehyde group or epoxy group. Selected from the group 1
Urethane reaction, ureation reaction between functional groups of at least one species,
It is bonded by reactions such as esterification reaction, acetalization reaction, etherification reaction, etc. to form a polymer having both a strong film-forming ability and a releasing performance.

The long-chain alkyl compound having an isocyanate group, for example, octyl isocyanate, dodecyl isocyanate, octadecyl isocyanate, docosanyl isocyanate, and a compound having a carboxyl group, for example, octanoic acid, dodecanoic acid,
Octadecanoic acid, docosanoic acid, as those having an acid halide group, for example, octanoyl chloride, dodecanoyl chloride, octadecanoyl chloride, docosanoyl chloride, as those having a ketene group, for example, octyl ketene dimer, dodecyl ketene dimer, Octadecyl ketene dimer, docosanyl ketene dimer, those having an aldehyde group, for example, octyl aldehyde, dodecyl aldehyde, octadecyl aldehyde, docosanyl aldehyde, those having an epoxy group, for example, octyl glycidyl ether, dodecyl glycidyl ether, octadecyl glycidyl Examples thereof include ether and docosanyl glycidyl ether.

With respect to 1 equivalent of hydroxyl group of the vinyl acetate copolymer having (a) the degree of polymerization of 300 to 5,000 and the degree of saponification of 50 mol% or more, (b) an isocyanate group, a carboxyl group and an acid halide. Group, a ketene group, an aldehyde group, an epoxy group, having one or more functional groups that react with hydroxyl groups and having 6 to 6 carbon atoms.
0.5 for long-chain alkyl compounds having 30 alkyl groups
The release agent component [1] is synthesized by reacting at a ratio of not less than equivalent, preferably not less than 0.6 equivalent, but when the reaction equivalent is less than 0.5 equivalent, the release agent obtained is released. Performance deteriorates. There is no particular upper limit to the reaction equivalent, but if added in excess, unreacted substances will increase and separation will take time.

When one or more kinds of functional groups which react with the hydroxyl group in the long chain alkyl compound (b) having an alkyl group having 6 to 30 carbon atoms are an isocyanate group or a ketene group, the dispersion used for the above reaction As the medium, an inert liquid such as toluene or dimethyl sulfoxide that does not react with isocyanate or ketene is selected, and the reaction is carried out by suspending or dissolving in the liquid.

When the one or more functional groups that react with the above-mentioned hydroxyl groups are carboxyl groups, the reaction is carried out in a solvent such as toluene which is commonly used in esterification reactions.

When the one or more functional groups that react with the hydroxyl groups are acid halide groups, an inert liquid is selected,
The reaction is carried out by suspending or dissolving in the liquid, and in this reaction, it is preferable to add a dehydrohalogenating agent such as pyridine. Reacts with the above hydroxyl groups 1
An inert liquid is selected even when the one or more functional groups are aldehyde groups, and the reaction is carried out by suspending or dissolving in the liquid. In this reaction, an acid such as hydrochloric acid is used. It is preferred to add a catalyst.

When the one or more functional groups that react with the hydroxyl group is an epoxy group, an inert liquid is selected, and the reaction is carried out by suspending or dissolving in the liquid. In this reaction, For example, it is preferable to add an alkali catalyst such as sodium hydroxide. These reactions are terminated after confirming that the hydroxyl group or the functional group that reacts with the hydroxyl group has substantially disappeared due to infrared absorption or the like.

The [2] fatty acid having 10 to 30 carbon atoms, preferably 12 to 26, is a saturated fatty acid having 10 to 30 carbon atoms, preferably 12 to 26 carbon atoms, or a fatty acid having 10 to 30 carbon atoms, preferably 12 to 26 carbon atoms. Any of saturated fatty acids may be used, and these may be used alone or in combination of two or more kinds. The carbon number is 10
When it is less than the above range, the polarity is large and the release agent component is separated from the release agent composition or the melting point of the release agent composition is lowered, which adversely affects the release performance. When the number of carbon atoms is more than 30, the polarity becomes small and the water dispersibility becomes difficult to decrease, or the melt viscosity becomes large and the water-dispersible release agent composition is applied to a release sheet base material and then released. This has an unfavorable effect such as a long heating time until the mold performance is exhibited.

Examples of the above [2] fatty acids having 10 to 30 carbon atoms, preferably 12 to 26, include, for example, dodecanoic acid (lauric acid), hexadecanoic acid (palmitic acid), octadecanoic acid (stearic acid), octadecenoic acid (olein). Acid), icosanoic acid (arachidic acid), docosanoic acid (behenic acid) and the like. However, these fatty acids are in the form of these metal salts in the presence of hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide and barium hydroxide, but these metal salts are also It has the same function and can be used in the present invention in the same manner as the above fatty acids.

The amount of the above [2] fatty acid having 10 to 30 carbon atoms, preferably 12 to 26, is [1] (a) the degree of polymerization is 300 to 5000, and the degree of saponification is 50 mol% or more. For one equivalent of hydroxyl group of a vinyl acetate copolymer,
(B) having at least one functional group that reacts with a hydroxyl group, selected from the group consisting of an isocyanate group, a carboxyl group, an acid halide group, a ketene group, an aldehyde group, and an epoxy group, and having 6 to 30 carbon atoms The amount is preferably 1 to 50 parts by weight, more preferably 3 to 40 parts by weight, relative to 100 parts by weight of the component obtained by reacting the long chain alkyl compound having an alkyl group of 0.5 equivalent or more.

If the blending amount is less than 1 part by weight, the dispersibility of the release agent component is lowered and the coating properties of the water-dispersed releasing agent composition are adversely affected, and the blending amount is 50 parts by weight. When it exceeds, the transferability of the above-mentioned release agent composition to the pressure-sensitive adhesive layer becomes large, which is not preferable.

The acid-modified polyolefin (co) polymer [2] having an acid value of 0.2 to 800 has an acid value of 0.2 to 80.
0, preferably 10 to 200, for example, a copolymer of an olefin such as ethylene, propylene and 1-butene with a monomer having an acid group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and vinylpyrrolidone. And polyolefin-based (co) polymers such as polyethylene, polypropylene, and poly (1-butene) that have been chemically or physically oxidized. Specific examples include maleic acid-modified polyethylene wax and acrylic acid-modified polyethylene wax. Polyethylene wax is preferably used.

When the acid value of the acid-modified polyolefin-based (co) polymer [2] having an acid value of 0.2 to 800 is less than 0.2, the dispersibility in water is lowered and aggregation or sedimentation occurs. When the acid value exceeds 800, the polarity becomes too large, the compatibility with the release agent component decreases, and in an extreme case, separation occurs.

When the above [2] acid-modified polyolefin (co) polymer having an acid value of 0.2 to 800 is a copolymer of the above-mentioned olefin and a monomer having an acid group, the acid group is The copolymerization ratio of the monomers contained therein is preferably 0.01 to 40 mol%, more preferably 0.5 to 10 mol%. The degree of polymerization of the acid-modified polyolefin-based (co) polymer having an acid value of [2] of 0.2 to 800 is preferably 10 to 2000, more preferably 200 to 1000.

When the degree of polymerization is less than 10, the softening temperature is lowered and the release performance is deteriorated. When the degree of polymerization exceeds 2000, the dispersibility in water decreases, and the heating time after the water-dispersible release agent composition is applied to a release sheet substrate until the release performance is exhibited. Will have an unfavorable effect, such as a long time.

The melting point of the acid-modified polyolefin (co) polymer [2] having an acid value of 0.2 to 800 is preferably 4
The melt viscosity at 0 ° C or higher and 140 ° C is preferably 1
0000 (Pa · s) or less, more preferably the melting point is 6
The melt viscosity at 0 ° C or higher and 140 ° C is 5000 (P
a · s) or less. When the melting point is less than 40 ° C,
The release performance of the water-dispersed release agent composition is adversely affected, and the melt viscosity at 140 ° C. is 10,000 (Pa
When the melting point and the melt viscosity are increased to an extent exceeding .s), the dispersibility in water decreases, and the release performance is exhibited after the above water-dispersed release agent composition is applied to a release sheet base material. It has unfavorable effects such as long heating time.

The compounding amount of the above [2] acid-modified polyolefin-based (co) polymer having an acid value of 0.2 to 800 is [1]
(A) Hydroxyl group 1 of vinyl acetate copolymer having a degree of polymerization of 300 to 5000 and a degree of saponification of 50 mol% or more.
With respect to the equivalent weight, (b) has at least one functional group that reacts with a hydroxyl group selected from the group consisting of an isocyanate group, a carboxyl group, an acid halide group, a ketene group, an aldehyde group, and an epoxy group, and carbon 1 to 50 parts by weight, more preferably 3 to 40 parts by weight, relative to 100 parts by weight of a component obtained by reacting a long-chain alkyl compound having an alkyl group of several 6 to 30 at a ratio of 0.5 equivalent or more. Is.

If the blending amount is less than 1 part by weight, the dispersibility of the release agent component is lowered and the coating properties of the water-dispersible releasing agent composition are adversely affected, and the blending amount is 50 parts by weight. When it exceeds, the transferability of the above-mentioned release agent composition to the pressure-sensitive adhesive layer becomes large, which is not preferable.

The above [2] acid-modified polyolefin type (co) polymer having an acid value of 0.2 to 800 is the above [2] carbon number 10
When used in combination with a fatty acid of -30, preferably 12-26, the total amount of both may be 1-50 parts by weight, more preferably 3-40 parts by weight.

The above-mentioned water-dispersion type release agent composition used in the present invention may have water dispersibility enhanced or, if necessary,
To reinforce the wettability at the time of application and to suppress foaming,
A high-boiling-point liquid substance, a surfactant, and a cross-linking agent for reinforcing the coating strength after coating may be added as described below.

The high boiling point liquid substance has a boiling point at atmospheric pressure higher than 100 ° C. and a viscosity at room temperature of 100,000 (m).
A high boiling point liquid substance having a viscosity of Pa · s or less is preferably used.
Examples of the high-boiling-point liquid substances include naphthene-based oils, lanolin, oligomers of olefins, process oils such as vegetable oils, animal oils and mineral oils, liquid tackifying resins such as liquid rosin and turpentine oil, and plasticizers such as polybutene and diisodecyl phthalate. Agents and the like. Since the high-boiling-point liquid substance is usually also used as a softening agent in an adhesive, the high-boiling-point liquid substance in the water-dispersed release agent composition is applied and dried, and then the release sheet is released. Remains in the mold layer,
Even when it moves to the pressure-sensitive adhesive layer when it comes into contact with the pressure-sensitive adhesive layer, it does not significantly affect the pressure-sensitive adhesive property of the pressure-sensitive adhesive, considering the properties of the high-boiling-point liquid substance and the amount transferred from the thin release layer.

When the boiling point of the high boiling point liquid substance is 100 ° C. or lower, it is volatilized in the drying step during the production of the release sheet, and the desired effect cannot be sufficiently exerted, and also from the viewpoint of safety and environment. It is annoying that additional equipment is required. Also, the viscosity of the high boiling point liquid substance at room temperature is 100,000 (mP
If it exceeds a · s), the fluidity of the water-dispersed release agent composition is lowered, which adversely affects the film-forming performance.

As the above surfactant, any of nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants can be used. The nonionic surfactant, polyoxyethylene alkyl phenyl ether, ether type such as polyoxyethylene alkyl ether, glycerin fatty acid ester, sorbitan fatty acid ester, ester type such as sucrose fatty acid ester,
Examples thereof include ester ether type surfactants such as polyethylene glycol fatty acid ester and polyoxyethylene sorbitan fatty acid ester, and fatty acid alkanolamide type surfactants.

Examples of the above-mentioned anionic surfactants include carboxylic acid salt types such as fatty acid monocarboxylic acid salts and N-acylloylglutamates, alkylbenzene sulfonates, naphthalene sulfonate-formaldehyde condensates, sulfosuccinic acid dialkyl esters. Examples thereof include sulfonic acid type surfactants such as, and sulfate ester type surfactants such as alkyl sulfates, and phosphoric acid ester type surfactants such as alkyl phosphate salts.

Examples of the above cationic surfactants include amine salt type surfactants such as alkylamine salts and quaternary ammonium salt type surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts and alkyldimethylbenzylammonium salts. To be

As the above-mentioned amphoteric surfactant, carboxybetaine type such as N, N-dimethyl-N-alkylaminoacetic acid betaine, 2-alkyl-1-hydroxyethyl-
Examples thereof include glycine type surfactants such as 1-carboxymethylimidazolinium betaine.

The cross-linking agent reacts with the release agent component in the water-dispersed release agent composition by applying heat, light or the like after coating the water-dispersed release agent composition on a substrate. However, it is not particularly limited as long as it can crosslink these release agent components, for example, polyvalent isocyanate compound, blocked polyvalent isocyanate compound, polyvalent epoxy compound, polyvalent acryloyl compound, Examples thereof include a valent methylol compound, a polyvalent aziridine compound, and a polyvalent ionic metal.

The means for preparing a water-dispersed release agent from each component of the water-dispersed release agent composition is not particularly limited, but the water-dispersed release agent composition is dissolved in an organic solvent. After that, it is mixed with water while stirring with a high-speed emulsifying machine to emulsify and disperse, and then the above-mentioned water-dispersed release agent composition is heat-melted and added without using a solvent dissolution method excluding an organic solvent or an organic solvent. There is a method such as a high pressure emulsification method in which a mixture is mixed and emulsified with water while applying a high shearing force with a pressure kneader, a colloid mill, a high speed stirring shaft or the like.

The above-mentioned high-pressure emulsification method is a preferable method because it can be worked without using an organic solvent, and it is in agreement with the gist of the present invention.

The above-mentioned high-pressure emulsification method is specifically carried out by the following procedure. First, the water-dispersed release agent composition is melt-mixed at, for example, 120 ° C. or higher, and then the melt of the water-dispersed release agent composition and water at 100 ° C. or higher are heated under pressure. Either by mixing while applying a shearing force, or by adding the above water-dispersed release agent composition and water all at once, and heating under pressure, for example, at 120 ° C. or higher, and mixing while applying a high shearing force. , Disperse in water. Then, the dispersion liquid in the above dispersion liquid is cooled so as not to cause secondary aggregation, to prepare a water-dispersed release agent.

In the method for producing a release sheet of the present invention, the water-dispersed release agent composition dispersed in water is applied to a substrate and dried, and then the water-dispersed release agent composition. The feature is that the release agent component is melted and smoothed by pressurizing the coated surface under heating.

The above-mentioned base material is not particularly limited as long as it is flexible enough to be adhered to the pressure-sensitive adhesive layer so that it can be adhered and has sufficient strength to be peeled from the adhered surface.
For example, polyethylene, polypropylene, polyester, plastic films such as cellophane, fine paper,
Paper such as kraft paper, crepe paper, glassine paper, impregnated paper, plastic coated paper, etc.
Examples include cloths. It is preferable that the surface of these base materials is subjected to surface treatment such as corona discharge treatment, plasma treatment, or primer treatment, if necessary, in order to enhance the adhesion with the release agent.

Means for applying the water-dispersed release agent composition to the above-mentioned substrate is not particularly limited, but for example, a coating device such as a roll coater, a gravure coater, a Mayer bar coater, a lip coater or the like is used. The coating film composed of the water-dispersed release agent composition formed on the base material by coating is removed by evaporating water in a drying furnace.

According to the observations of the present inventors, the water-dispersible release agent was dispersed in water when the water was simply evaporated from the coating film in the drying furnace. It is in the form of fine particles and is adhered on the base material in a single layer or in a laminated form, the adhesion to the base material is not sufficient, and the releasability and the non-migrating releasability are not sufficiently exhibited. It has been found.

In the method for producing a release sheet of the present invention, in the above drying oven, a release layer obtained by evaporating water from the coating film and in which the release performance is not sufficiently developed is pressed under heating to release the release agent. By melting and smoothing the components, it is possible to extremely efficiently develop the adhesiveness to the base material and the releasing property of non-migrating and non-migrating properties in a short time. .

The means for pressurizing under heating is not particularly limited, but for example, the above-mentioned substrate provided with a coating film of a dried water-dispersible release agent between a pair of pressurizing and heating rolls. A method of pinching and passing is preferably used in terms of productivity and the like. The heating temperature must be higher than the softening point of the fine particles of the water-dispersed release agent, and is usually 60 ° C. or higher, preferably 80 ° C. or higher. The upper limit of the heating temperature depends on the heat resistance of the substrate. The pressure is 0.01
It is preferably about 500 kg / cm ^{2 and the} highest possible pressure, but the upper limit depends on the pressure resistance of the substrate.

The material of the pressurizing and heating roll is a rubber roll of a material such that the adhesiveness at the interface between the release agent and the rubber roll is smaller than the adhesiveness at the interface between the release agent and the substrate during pressurizing and heating. It is required that the rubber roll has elasticity to give a uniform clamping force over the entire width of the rubber roll under the above-mentioned use conditions. As a roll satisfying such requirements, for example, a heat resistant silicone lining roll or a heat resistant Teflon lining roll is preferably used.

From the standpoint of productivity, the pressurizing and heating roll is continuously operated in a series of devices following each step of coating and drying. Therefore, immediately after the drying furnace, the line speed of each of the coating and drying devices is increased. It is installed in sync with. Therefore, the diameter of the pressure heating roll is determined by the time required for the heat treatment by the pressure heating roll and the line speed thereof.

[0058]

According to the method for producing a release sheet of the present invention as set forth in claim 1, a water-dispersed release agent composition dispersed in water is applied to a substrate and dried, and then the water-dispersed type is prepared. Since the surface of the release agent composition coated is heated and melted to melt and smooth the release agent component, it is extremely efficient in a short time treatment, and the adhesiveness to the substrate and the release property The transferability of the mold can be sufficiently expressed.

In the method for producing a release sheet of the present invention according to claim 2, the water-dispersed release agent composition [1] (a) has a degree of polymerization of 300 to 5000, and
(B) is selected from the group consisting of an isocyanate group, a carboxyl group, an acid halide group, a ketene group, an aldehyde group, and an epoxy group with respect to 1 equivalent of a hydroxyl group of a vinyl acetate copolymer having a saponification degree of 50 mol% or more, React with hydroxyl groups 1
A component obtained by reacting a long-chain alkyl compound having at least one kind of functional group and having an alkyl group having 6 to 30 carbon atoms at a ratio of 0.5 equivalent or more, and [2] having 10 to 3 carbon atoms.
One or more fatty acids of 0 and / or an acid value of 0.2 to 800
2. The method for producing a release sheet according to claim 1, wherein the acid-modified polylefin-based (co) polymer component is dispersed in water, so that a release layer excellent in releasability and non-migratory property is obtained. In addition to forming, it is possible to draw characters and patterns on the release-treated surface with magic ink etc. (drawability), and further apply an adhesive tape to the release-treated surface such as an adhesive tape using the release sheet. Since it can be stacked (lapable), sealing can be done reliably, and there is difficulty in slipping between the release treated surfaces (non-slip), making it possible to store corrugated packaging in multiple stages during storage. It is possible to form the release layer having excellent performance such that the load does not easily collapse even when stacked, in a short time and extremely efficiently.

[0060]

EXAMPLES Examples of the present invention will be described below.

[Preparation of Release Agent Components R-1, R-2 and R-3] In a reaction vessel equipped with a stirrer, a cooler and a dropping funnel, polyvinyl alcohol (polymerization degree 1100, saponification degree 9
10 parts by weight (8 mol%) are dispersed in 50 parts by weight of dehydrated xylene. 67 parts by weight of octadecyl isocyanate at the reflux temperature and 0.01 parts of catalyst (dibutyltin dilaurate)
Add parts by weight and react with polyvinyl alcohol. As the reaction progresses, the polyvinyl alcohol powder decreases, but the reaction is continued for 2 hours after the powder disappears. Then, it was cooled to 40 ° C., and the obtained reaction solution was added to 1
Pour into 000 parts by weight of methanol to obtain a white precipitate. This was washed with methanol and then with hexane and dried to prepare a release agent component R-1.

The release agent component R-2 was replaced with the release agent component R-1 of polyvinyl alcohol, and an ethylene / vinyl alcohol copolymer (polymerization degree 1500, saponification degree 69 mol%, ethylene copolymerization ratio 30 mol%) was used. ) Was used, and the amount of octadecyl isocyanate compounded was changed from 67 parts by weight to 57 parts by weight, and the release agent component R-1 was prepared in the same manner.

The mold release agent component R-3 was prepared by dehydrating 10 parts by weight of the ethylene / vinyl alcohol copolymer of the mold release agent component R-2 in a reaction vessel equipped with a stirrer, a cooler and a dropping funnel. Disperse throughout the section. Add 80 parts by weight of octadecyl chloride at 80 ° C. and react with ethylene / vinyl alcohol copolymer. As the reaction progresses,
Although the ethylene / vinyl alcohol copolymer powder decreases, the reaction is continued for 2 hours after the powder disappears.
Then, it was cooled to 40 ° C., and the obtained reaction solution was added to 150
Pour into 0 part by weight of methanol to obtain a white precipitate. This was washed with methanol and then with hexane and dried to prepare a release agent component R-3.

[Acid-modified polyolefin resin] ethylene /
Acrylic acid copolymer (degree of polymerization 250, acrylic acid copolymerization ratio 4 mol%)

[Surfactant] Alkyl diphenyl ether disulfonate (manufactured by Kao, trade name: Perex SS)
-L) 50% by weight, polyoxyethylene nonylphenyl ether (manufactured by Kao, trade name: Emulgen 910) 50
Wt% mixture

Example 1 Release Agent Component (R-1) 160
Parts by weight, 30 parts by weight of stearic acid, 10 parts by weight of surfactant and 800 parts by weight of water are mixed and placed in a 3 L high-pressure emulsifier, and stirred at 120 ° C. at a low speed of 500 rpm for 10 minutes to prepare a release agent component. (R-1) and stearic acid are brought into a molten state. Next, the temperature is raised to 135 ° C. and 5000 rpm
After stirring at high speed for 1 hour, the mixture was cooled to prepare a water-dispersed release agent composition.

A release agent obtained by diluting the obtained water-dispersed release agent composition with water so that the release agent component (R-1) was 3% by weight was used, and the basis weight of the substrate was 75 mg / m ^2. Polyethylene is extrusion-laminated to a thickness of 20 μm on Curupack kraft paper, and the coating amount (wet) 8 is applied to the polyethylene surface of the corona discharge treated (44 dyne / cm) sealing paper using a # 8 Meyer bar coater. It was applied at 0.5 g / m ² .

Then, the base material coated with the above-mentioned release agent is
It was supplied at a line speed of 4 m / min (the time required to process a unit length of 1 m is 15 seconds) into a drying furnace having a furnace length of 1 m and a temperature of 120 ° C. and dried. Further, two special silicone rubber lining rollers (long length) of a laminator (manufactured by MCK Co.) pressurized and heated to a gauge pressure of 2 kg / cm ² and a temperature of 120 ° C., which are synchronized with the line speed in the coating machine and the drying furnace. The release agent component on the base material was melted and smoothed through a space of 700 mm, a diameter of 60 mm and a hardness of 40) to produce a release sheet.

(Examples 2 to 6) The release agent component of Example 1,
A release sheet was prepared in the same manner as in Example 1 except that the fatty acid and acid-modified polyolefin (co) polymers were changed to the formulations shown in Table 1.

(Comparative Examples 1 to 4) The heating time (line speed) in the drying furnace of Example 1 was changed as shown in Table 1, except that the pressure heat treatment by the laminator was not performed.
A release sheet was produced in the same manner as in Example 1.

Comparative Examples 5 to 7 The water-dispersed release agent composition of Example 1 was mixed with toluene as an organic solvent to form a release agent component (R-
1) was diluted to 3% by weight to obtain a release agent, and the heating time in the drying furnace (adjusted by the line speed) was doubled as shown in Table 1, and pressure heating treatment by the laminator was not performed. A release sheet was produced in the same manner as in Example 1 except for the above.

In order to evaluate the performance of the release sheets obtained in the above Examples and Comparative Examples, the spreading force and the residual adhesive force were measured by the following methods. The measurement results are shown in Tables 1 and 2.

Spreading power : Using an adhesive tape (manufactured by Sekisui Chemical Co., Ltd., trade name: Sekisui Craft Tape # 504) cut into a strip having a width of 25 mm, JIS Z 02
According to 37, the release sheet was attached to the release-treated surface, left at 23 ° C. for 24 hours, and then subjected to a 180 ° peel test at a speed of 10 m / min using a high-speed peel tester.

The peeling force of the release sheet was evaluated by displaying the peeling force in the peeling test as a developing force.

Residual adhesive force : A peeling test was conducted in the same manner as the test of the developing force in the preceding paragraph, and the pressure-sensitive adhesive tape peeled from the release-treated surface of the obtained release sheet was subjected to JIS Z 0.
According to 237, affix to a stainless steel plate and
After standing for 4 hours, a 180 ° peeling test was performed at a speed of 300 mm / min.

The adhesive strength in the peeling test (2010) is not affected by the history of peeling the adhesive strength in the peeling test from the release treated surface.
The percentage of the value divided by (g / 25 mm) was displayed as the residual adhesive force, and the non-migration property of the release agent of the release sheet to the pressure-sensitive adhesive layer was evaluated.

[0077]

[Table 1]

[0078]

[Table 2]

As can be seen from the comparison between each of the above Examples and Comparative Examples 1 to 4, the release sheet manufacturing method of the present invention comprises:
The total treatment time for sufficiently exhibiting the performance of the water-dispersed release agent composition was 6 compared to the conventional method of Comparative Example.
It can be seen that 0 second is shortened to 1/2 to 1/3, which is 20 to 30 seconds. In addition, although the conventional method using an organic solvent is shown for reference in Comparative Examples 5 to 7, the release performance can be obtained at the same efficiency, but the use of the organic solvent increases the equipment cost. , There are troublesome problems such as having to deal with various environmental and pollution problems.

[0080]

EFFECTS OF THE INVENTION Since the method for producing a release sheet of the present invention is constructed as described above, it is very efficient in a short time treatment, and the adhesiveness to the substrate and the releasability and non-migration property are excellent. Excellent mold release performance can be exhibited. Further, in the method for producing a release sheet according to the present invention as set forth in claim 2, in addition to the excellent release performance of the adhesiveness to the substrate and the release property and the non-migration property,
Characters, patterns, etc. can be drawn on the release-treated surface with magic ink or the like (drawability), and an adhesive tape or the like can be further laminated on the release-treated surface such as an adhesive tape using the release sheet ( Because it can be pasted together, it is possible to securely seal heavy packages, etc.
Furthermore, a release sheet with excellent performance that is difficult to slip between the release-treated surfaces (non-slip property) and does not easily collapse even when stacking cardboard-packaged packages in multiple stages such as during storage. It can be manufactured.

Continuation of front page (56) Reference JP-A-6-179249 (JP, A) JP-A-57-20354 (JP, A) JP-A-2-141214 (JP, A) JP-A-5-245922 (JP , A) JP-A 1-229045 (JP, A) JP-A 8-299895 (JP, A) JP-A 58-52396 (JP, A) JP-A 51-13836 (JP, A) JP-A 63-220871 (JP, U) JP-A-4-131236 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 C08L 1/00-101 / 14 C09J 7/00-7/04 C09K 3/00

Claims (2)

(57) [Claims] 1. A water-dispersed release agent composition dispersed in water is applied to a substrate and dried, and then the surface coated with the water-dispersed release agent composition is pressed under heating. Melting release agent component,
A method for producing a release sheet, which comprises smoothing. 2. A water-dispersed release agent composition comprising [1] (a)
The degree of polymerization is 300 to 5000, and the degree of saponification is 50.
React with a hydroxyl group selected from the group consisting of (b) an isocyanate group, a carboxyl group, an acid halide group, a ketene group, an aldehyde group and an epoxy group with respect to 1 equivalent of the hydroxyl group of the vinyl acetate copolymer which is at least mol%. A component obtained by reacting a long-chain alkyl compound having one or more functional groups and having an alkyl group having 6 to 30 carbon atoms at a ratio of 0.5 equivalent or more, and [2] having 10 to 10 carbon atoms. The method for producing a release sheet according to claim 1, wherein one or more of 30 fatty acids and / or an acid-modified polyolefin (co) polymer component having an acid value of 0.2 to 800 is dispersed in water. .