TW201941950A - Release sheet - Google Patents

Abstract

The present invention provides a release sheet which has a small change in the peeling force over time, and is a release layer that is stable even when the initial peeling force is set to be high at high temperature storage. The peeling sheet has a base material and a peeling layer. The release layer is a layer formed of a release agent composition containing a polybutadiene (A) having a crosslinkable functional group and a melamine compound (B), and the crosslinkable functional group and a melamine compound (B The functional group to be reacted, and the polybutadiene (A) having a crosslinkable functional group includes 50 mol% or more of 1,2-vinyl based on all the constituent units of the polybutadiene (A).

Description

Peel sheet

The present invention relates to a release sheet.

Generally, a release sheet has a substrate such as paper, a plastic film, or a polyethylene laminate paper, and a release layer provided on the substrate. The peeling layer is formed by applying a peeling agent composition containing a reactive compound on a substrate and curing it.
The release sheet has been widely used as, for example, a protective sheet for an adhesive layer provided in an adhesive sheet, a step film for producing a resin sheet, a step film for forming a ceramic green sheet sheet, and a step film for producing a synthetic leather.

As a release agent composition for forming a release layer, a silicone-based release agent composition containing a silicone compound such as a silicone resin, silicone, or silicone oil has been widely used.
However, the silicon oxide compound may migrate to the contact surface with the release layer, for example, the surface of the adhesive layer of the adhesive sheet. Also, it will gradually gasify after migration.
Therefore, when a release sheet having a release layer formed of a silicone-based release agent composition is used in an electronic material application, the silicon-oxygen compound migrates to the electronic part, and the electronic part may be corroded or may cause a malfunction.

Therefore, the formation of a release layer without using a silicone-based release agent composition has been reviewed.
When using a release layer formed of a non-silicone-based release agent composition, the peeling force of the object laminated on the release layer is generally higher than that of a release layer formed from a silicone-based release agent composition. However, in the case where the laminating object has a higher retention (fall-off resistance), the peeling force is higher and better, so a non-silicone release agent composition is often selected.
As such a non-silicone type release agent composition, for example, Patent Literature 1 describes a release sheet having a release layer formed of a release agent composition containing at least a polyolefin and 3 in one molecule. Isocyanates with more than one isocyanate group, and polyolefin polyols.
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2011-52207

[Questions to be Solved by the Invention]

However, a peeling layer formed of a peeling agent composition other than the silicone-based peeling agent composition has a large change in peeling force with time, and the peeling force easily increases with time. In particular, when the peeling force of the peeling layer is set to be high, the change with time tends to be large, and the peeling force is high and the stable peeling layer is relatively rare.

Therefore, an object of the present invention is to provide a release sheet which has a small change in the peeling force over time, and is a release layer that is stable even when the initial peeling force is set to be high at high temperature storage.

[Means to solve the problem]

The present inventors have found that a release sheet having a release layer formed of a release agent composition containing a specific polybutadiene and a melamine compound can solve the above-mentioned problems.

That is, the present invention relates to the following [1] to [5].
[1] A release sheet, which is a release sheet having a substrate and a release layer,
The release layer is a layer formed of a release agent composition containing a polybutadiene (A) having a crosslinkable functional group and a melamine compound (B), and the crosslinkable functional group is reacted with the melamine compound (B) The functional group and the polybutadiene (A) having a crosslinkable functional group include 50 mol% or more of 1,2-vinyl based on all the constituent units of the polybutadiene (A).
[2] The release sheet according to the above [1], wherein the crosslinkable functional group is a hydroxyl group.
[3] The release sheet according to the above [1] or [2], wherein the polybutadiene (A) having a crosslinkable functional group is a hydrogen additive having a bromine value of 10 g / 100 g or less.
[4] The peeling sheet according to any one of the above [1] to [3], wherein the peeling force of the aforementioned peeling sheet after 7 days of exposure in a high-temperature environment at a temperature of 70 ° C. is set as a peeling force after heating Y When the peeling force of the peeling sheet that is not exposed to the high temperature environment is the initial peeling force X, {(peeling force after heating Y-initial peeling force X) / initial peeling force X} × 100 is expressed as The change rate is within ± 30%.
[5] The peeling sheet according to any one of the above [1] to [4], wherein the peeling force when peeling from the adhesive layer is 2500 mN / 20 mm or more.

[Inventive effect]

According to the present invention, it is possible to provide a peeling sheet having a peeling force with a small change in peeling force over time, and a stable peeling force even when the initial peeling force is set to be high at high temperature storage.

In this specification, the number average molecular weight (Mn) is a value converted into a standard polystyrene by a gel permeation chromatography (GPC) method.
In this specification, the "active ingredient" means a component other than a diluent solvent among the components contained in the release agent composition.

[Composition of release sheet]
The release sheet of the present invention has a substrate and a release layer provided on the substrate.
FIG. 1 is a schematic cross-sectional view of a release sheet according to an aspect of the present invention. The release sheet 1 includes a substrate 10 and a release layer 11 provided on the substrate 10. The release layer 11 is a crosslinked product formed of a release agent composition containing a specific polybutadiene (A) and a melamine compound (B).
In addition, other layers such as an easy-to-adhere layer and an antistatic layer (not shown) may be provided between the substrate 10 and the release layer 11.
Hereinafter, the release layer and the base material constituting the release sheet of the present invention will be described.

＜ Peeling layer ＞
The release layer of the release sheet of the present invention can be formed of a release agent composition containing a specific polybutadiene (A) and a melamine compound (B).
Hereinafter, the release agent composition of the release agent forming material will be described.
In addition, in the following description, "the content of each component with respect to the total amount of active ingredients in a release agent composition" is considered to be "the content of each component in a release agent layer formed from the release agent composition".

(Stripping agent composition)
The release agent composition contains a specific polybutadiene (A), that is, has a crosslinkable functional group, and contains 50 mol% of 1,2-vinyl body based on the entire constituent unit of the polybutadiene (A). The above polybutadiene (A) and the melamine compound (B).
In addition, in the following description, "a cross-linkable functional group includes polybutadiene (A) containing 50 mol% or more of 1,2-vinyl based on all constituent units of polybutadiene (A). "Sometimes referred to as" polybutadiene (A) ".

The present inventors have pointed out that for a release agent composition other than the silicone-based release agent composition, a time-dependent change in the peeling force of a release layer formed from the release agent composition can be reduced, and the method is used to ensure sufficient film strength. Conduct various reviews. As a result, it was found that the combination had a crosslinkable functional group, and contained polybutadiene (A) and melamine at 50 mol% or more of 1,2-vinyl based on all constituent units of polybutadiene (A) as a basis. Compound (B) is effective.
In addition, it was also found that when using an isocyanate compound instead of a melamine compound as a cross-linking agent, even if a cross-linkable functional group is used, it includes 1,2-vinyl based on all the constituent units of polybutadiene (A). Polybutadiene (A) of 50 mol% or more cannot ensure film strength.
Based on these results, the present inventors have discovered that the polymer having a crosslinkable functional group and containing polybutadiene (A) as the basis of all constituent units of 50 mol% or more of 1,2-vinyl is included. The release sheet of a release agent layer formed of a release agent composition of butadiene (A) and melamine compound (B) can solve the above problems, and thus completed the present invention.

Moreover, in one aspect of the present invention, the release agent composition may contain additives other than the above-mentioned components (A) and (B) as long as the effect of the present invention is not impaired.

Hereinafter, each component contained in a release agent composition is demonstrated.

(Polybutadiene (A))
In the present invention, as the polybutadiene (A), a crosslinkable functional group is used, and the content of the polybutadiene (A) is 50 mol% or more based on 1,2-vinyl based on all the constituent units of the polybutadiene (A). Polybutadiene.
In the present specification, the "crosslinkable functional group" means a functional group that reacts with the melamine compound (B) as a crosslinking agent.

The crosslinkable functional group in which polybutadiene (A) is polymerized is selected in a relationship with the melamine compound (B).
Examples of the crosslinkable functional group possessed by the polybutadiene (A) include a hydroxyl group, a carboxyl group, an epoxy group, an amine group, an isocyanate group, a thiol group, and a vinyl group.
Among these, from the viewpoint of better reactivity with the melamine compound (B), the crosslinkable functional group is preferably a hydroxyl group.
The polybutadiene (A) may have at least one crosslinkable functional group, and preferably has two or more crosslinkable functional groups. When the polybutadiene (A) has two or more crosslinkable functional groups, these functional groups may be the same as or different from each other, but they are preferably the same as each other.

The position of the crosslinkable functional group of the polybutadiene (A) is not particularly limited as long as the position of the crosslinkable functional group can react with the melamine (B).
Here, in one aspect of the present invention, from the viewpoint of increasing the distance between the cross-linking points to form a peeling layer with better peelability, the molecular chain constituting the polymer skeleton of polybutadiene (A) is preferably At least one terminal has a crosslinkable functional group, and more preferably, it has a crosslinkable functional group at both ends of the molecular chain constituting the polymer backbone of the polybutadiene (A), and more preferably, it constitutes a polybutadiene (A). The polymer backbone has a crosslinkable functional group only at both ends of the main chain.

The polybutadiene (A) includes 50 mol% or more of vinylene based on the entire constituent units of the polybutadiene (A).
Polybutadiene is a polymer in units of 1,4-cis isomer, 1,4-trans isomer, and 1,2-vinyl isomer. There are various commercial products of polybutadiene having different content ratios in each unit. In addition, polybutadiene having a different content ratio in each unit can also be synthesized by a predetermined method.
In the present invention, the use of polybutadiene (A) containing 50 mol% or more of vinylene based on all constituent units of polybutadiene (A) as a basis in the release agent composition can be used. A release sheet having a release layer showing a higher initial peel force and a small change in the peel force over time was obtained. The content of 1,2-vinyl in the release agent composition is less than 50 mole%, and one or both of 1,4-cis and 1,4-trans is high. The release layer formed of polybutadiene has a low initial peel force and a large change in the peel force over time.
The content of 1,2-vinyl in polybutadiene (A) is preferably 60 mol% or more, and from the viewpoint of easier synthesis of polybutadiene (A), more preferably 70 to 90 mol% , And more preferably 80 ~ 90 mole%.

The number average molecular weight (M _n ) of the polybutadiene (A) is preferably 1,000 to 30,000, more preferably 1,000 to 20,000, still more preferably 1,000 to 10,000, and even more preferably 1,000 to 5,000.

The polybutadiene (A) may be a hydrogen additive. The degree of hydrogenation of polybutadiene (A) may be partially hydrogenated or completely hydrogenated, but from the viewpoint of improving the chemical stability of the peeling force of the release layer, it is preferred to add a portion of the hydrogen with a lower residual rate of vinyl More preferably, it is a complete hydrogen additive.
From this viewpoint, it is preferred that polybutadiene (A) has a lower bromine value. When the bromine value is low, the residual vinyl group in polybutadiene (A) is low, and it is not susceptible to chemical changes such as oxidation. Therefore, the stability of the peeling force of the release layer over time tends to be good.
Specifically, the bromine value of the hydrogen additive of polybutadiene (A) is preferably 100 g / 100 g or less, more preferably 20 g / 100 g or less, still more preferably 10 g / 100 g or less, and even more preferably 8 g / 100 g. the following.
The bromine value is a value measured in accordance with JIS K 2605.
Moreover, polybutadiene (A) may be used individually by 1 type, and may be used in combination of 2 or more type. For example, in one aspect of the present invention, the polybutadiene (A) may be a mixture of a hydrogen additive and a non-hydrogen additive.

(Melamine Compound (B))
The melamine compound (B) is used as a cross-linking agent for polybutadiene (A), and is not particularly limited as long as it is a compound capable of performing a cross-linking reaction with a cross-linkable functional group of polybutadiene (A).
When the release agent composition contains the melamine compound (B), the film strength of the release layer formed by the release agent composition can be improved. Moreover, these effects cannot be obtained when an melamine compound is replaced with an isocyanate compound or the like.

The melamine compound (B) is preferably self-methylated melamine resin, imine methylolated melamine resin, methylated melamine resin, ethylated melamine resin, propylated melamine resin, butylated melamine resin, hexyl One or more types selected from the group consisting of melamine resin and octyl melamine resin.
Among these, one or more selected from the group consisting of methylolated melamine resin, imine methylolated melamine resin, and methylated melamine resin are more preferable, and methylated melamine resin is more preferable.

(Content and content ratio of polybutadiene (A) and melamine compound (B))
In one aspect of the present invention, the total content of the polybutadiene (A) and the melamine compound (B) in the release agent composition is based on the entire amount (100% by mass) of the release agent composition, and is preferably 70. More than mass%, more preferably 80 mass% or more, still more preferably 90 mass% or more, and even more preferably 95 mass% or more. When a solvent mentioned later is included, the total content of the polybutadiene (A) and the melamine compound (B) is an amount excluding the solvent (amount of active ingredient).

In one aspect of the present invention, the content ratio (A / B) of the polybutadiene (A) to the melamine compound (B) is better in terms of mass ratio from the viewpoint of further improving the stability of the release layer over time. 5/95 ~ 95/5, more preferably 10/90 ~ 90/10.
The range of the better content ratio (A / B) of the polybutadiene (A) and the melamine compound (B) varies depending on the value determined as the peeling force from the object to be laminated. For example, when a higher peeling force is required within the range of the peeling force of the peeling layer obtained by the composition of the polybutadiene (A) and the melamine compound (B), the polybutadiene (A) and the melamine compound (B) The better content ratio (A / B) is 5/95 ~ 30/70, more preferably 10/90 ~ 20/80 in terms of mass ratio. Conversely, when a lower peeling force is required within the range of the peeling force of the peeling layer obtained by the composition of the polybutadiene (A) and the melamine compound (B), the polybutadiene (A) and the melamine compound ( B) The better content ratio (A / B) is 70/30 ~ 95/5, more preferably 80/20 ~ 90/10 in terms of mass ratio.

(Acid catalyst)
In one aspect of the present invention, the release agent composition may further include an acid catalyst. By using an acid catalyst, the cross-linking reactivity of the polybutadiene (A) and the melamine compound (B) can be easily improved, and the time-dependent stability of the peeling force of the release layer can be further improved.
The acid catalyst is not particularly limited, but organic acid catalysts such as p-toluenesulfonic acid, methanesulfonic acid, and alkyl phosphate are preferred.
These acid catalysts may be used alone or in combination of two or more.
The amount of the acid catalyst is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and more preferably 100 parts by mass relative to the total amount of the polybutadiene (A) and the melamine compound (B). It is 1 to 5 parts by mass.

(Other additives)
In one aspect of the present invention, the release agent composition may contain additives other than the aforementioned components (A) and (B) and an acid catalyst as necessary.
Examples of such additives include various additives such as antioxidants, ultraviolet absorbers, inorganic or organic fillers, antistatic agents, surfactants, photoinitiators, light stabilizers, and the like.

(Silicone)
In one aspect of the present invention, the release agent composition is preferably substantially free of a silicon oxide compound.
The reason is that when a release sheet having a release layer formed of a release agent composition containing a silicon oxide compound is used for electronic materials, the silicon oxide compound may migrate to electronic parts, and the electronic parts may be corroded or may cause a malfunction.
In one aspect of the present invention, the content of the silicon oxide compound in the stripper composition is based on the total amount of the stripper composition (100% by mass), preferably less than 5.0% by mass, and more preferably less than 2.0% by mass. %, More preferably less than 1.0% by mass, even more preferably less than 0.1% by mass, and still more preferably less than 0.01% by mass.

(Isocyanate compound)
In the present invention, if a melamine compound (B) is blended in the release agent composition, other crosslinking agents may be used in combination or not. However, in one aspect of the present invention, the release agent composition preferably does not substantially contain isocyanate. Compound. The isocyanate compound is expected to react with the melamine compound (B) to form a crosslinked body when the functional group of the polybutadiene (A) is a hydroxyl group, but it cannot form a sufficient film as a release agent layer restricted by reaction conditions and the like. Moreover, when an unreacted isocyanate compound remains in a release agent layer, it may act | operate with the object of a lamination | stacking, and may raise the peeling force over time.
In one aspect of the present invention, the content of the isocyanate compound in the release agent composition is preferably less than 1.0% by mass, and more preferably less than 0.1% by mass based on the entire amount (100% by mass) of the release agent composition. It is still better to be less than 0.01% by mass, and even better to be less than 0.001% by mass.

(Non-reactive polyolefin)
In one aspect of the present invention, the release agent composition is preferably substantially free of a non-reactive polyolefin.
The "non-reactive polyolefin" in this specification means a non-hydrogen additive of a polyolefin which does not have a crosslinkable functional group or a hydrogen additive of a polyolefin which does not have a crosslinkable functional group.
When the release agent composition contains a non-reactive polyolefin, relatively few components are crosslinked in the release agent composition, which may reduce the film strength of the release layer. In addition, the solvent resistance may be reduced. Non-reactive polyolefins will bleed out, change over time or become contaminated during steps, and migrate towards the cast resin.
In one aspect of the present invention, as the non-reactive polyolefin content in the release agent composition, based on the entire amount (100% by mass) of the release agent composition, it is preferably less than 5.0% by mass, and more preferably less than 2.0. The mass% is still better than 1.0 mass%, even better is less than 0.1 mass%, and still better is less than 0.01 mass%.

(Poly (meth) acrylate)
In one aspect of the present invention, the release agent composition is preferably substantially free of poly (meth) acrylate.
In this specification, "(meth) acrylic" means both "acrylic" and "methacrylic".
When the poly (meth) acrylate does not have a crosslinkable functional group, there are relatively few components that are crosslinked in the release agent composition, and the film strength of the release layer may be reduced.
When the poly (meth) acrylate has a crosslinkable functional group, the proportion of the crosslinkable reactant of the hydrogen additive (A) of the polyolefin having a crosslinkable functional group and the melamine compound (B) in the release composition is relatively high. If it decreases, the peeling force of the peeling layer may decrease with time. In addition, there is a concern that the film strength of the release layer may decrease.
In one aspect of the present invention, the content of the poly (meth) acrylate having a crosslinkable functional group in the release agent composition is preferably based on the entire amount (100% by mass) of the release agent composition. 5.0% by mass, more preferably 2.0% by mass, more preferably 1.0% by mass, even better 0.1% by mass, and still better 0.01% by mass.

(Diluted solvent)
In one aspect of the present invention, from the viewpoint of improving the applicability to the substrate, the release agent composition may be added to the above-mentioned various active ingredients with a diluent solvent to form a solution form.
The diluting solvent is selected from organic solvents with good solubility of the components (A) and (B).
Examples of such organic solvents include toluene, xylene, heptane, octane, methanol, ethanol, isopropanol, isobutanol, n-butanol, ethyl acetate, acetone, methyl ethyl ketone, and cyclohexanone , Tetrahydrofuran, etc.
These can be used alone or in combination of two or more.
In addition, as the organic solvent used as the diluent solvent, the organic solvent used in the synthesis of the above-mentioned components (A) and (B) may be directly used, and the organic solvent used in the synthesis of the above-mentioned components (A) and (B) may be added and / Or one or more other organic solvents so that the release agent composition can be uniformly applied.

The amount of the diluting solvent may be appropriately selected so that the release agent composition has an appropriate viscosity when applied.
Specifically, the concentration of the effective component (solid content) contained in the solution of the release agent composition is preferably adjusted to be 0.1 to 15% by mass, more preferably 0.2 to 10% by mass, and more preferably 0.5 to 5% by mass. .

＜ Peel layer thickness ＞
The thickness of the release layer is not particularly limited, but is usually 25 to 1000 nm, and preferably 50 to 500 nm. When the thickness of the peeling layer is 25 nm or more, variations in peeling force due to variations in coating amount can be suppressed. Moreover, when the thickness of a peeling layer is 1000 nm or less, the hardenability of the coating film of a peeling agent composition can be made favorable.
The thickness of the release layer can be measured, for example, by a method described in Examples described later.

＜ Base material ＞
Examples of the base material used in the release sheet of the present invention include papers such as fine paper, clay coated paper, mirror-coated paper, kraft paper, laminated paper of thermoplastic resins such as laminated polyethylene resin, and synthetic paper. Paper sheets, polyolefin resins such as polyethylene resins, polypropylene resins; polybutylene terephthalate resins, polyethylene terephthalate resins, polyethylene terephthalate resins, etc. Polyester resins; polyether-imide resins; acetate resins; polystyrene resins; sheets of synthetic resins such as vinyl chloride resins.
The substrate may be a single layer or a multilayer of two or more layers of the same or different types.
The thickness of the substrate is not particularly limited, but it is usually 10 to 300 μm, and preferably 20 to 200 μm. If the thickness of the substrate is 10 to 300 μm, for example, an elasticity or strength suitable for processing such as printing, cutting, and attaching can be imparted to an adhesive sheet or the like using a release sheet.

When a synthetic resin is used as the base material, in order to improve the adhesion between the base material and the release layer, the surface of the base material on which the release layer is provided may be surface-treated by a method such as an oxidation method or an unevenness method as desired.
Examples of the oxidation method include corona discharge surface treatment, chromic acid surface treatment (wet), flame surface treatment, hot air surface treatment, ozone / ultraviolet irradiation surface treatment, and the like. Examples of the unevenness method include a sand blast method and a solvent treatment method. These surface treatment methods can be appropriately selected according to the type of the substrate, but in general, a corona discharge surface treatment method is preferably used from the viewpoints of effects and operability. It is also possible to perform a primer treatment.

In the release sheet of the present invention, embossing or the like may be performed on the surface on the release layer side to form unevenness on the surface of the release sheet.
In addition, the release sheet of the present invention may be provided with another layer such as an easy-adhesion layer, an antistatic layer, etc. between the substrate and the release layer. The release sheet has an easy-adhesion layer, which can effectively prevent the release layer from falling off from the release sheet.

The easy-adhesive layer is usually formed by applying an easy-adhesive coating agent to the surface of the release layer side of the substrate. Examples of the easy-adhesive coating agent include, for example, polyester resins, urethane resins, acrylic resins, melamine resins, oxazoline group-containing resins, carbon diamido-imide group-containing resins, Epoxy-based resins, isocyanate-containing resins, copolymers of these, and natural rubber or synthetic rubber-based coating agents.
These resins may be used singly or in combination of two or more kinds. In addition, in order to improve the applicability of the easily-adhesive coating agent to the surface of the substrate and the adhesion between the substrate and the easily-adhesive layer, the surface of the substrate that is easily adhered to the coating agent may be subjected to chemical treatment and discharge treatment. And other surface treatment.

The thickness of the easy-adhesive layer is preferably 50 nm or more, and more preferably 100 nm or more. The thickness is preferably 5 μm or less, and more preferably 1 μm or less. By setting the thickness to 50 nm or more, the effect of easily adhering a layer can be obtained satisfactorily. In addition, by setting the thickness to 5 μm or less, the smoothness of the surface of the easy-adhesive layer on the side opposite to the substrate can be improved, and the workability of applying the release agent composition to the easy-adhesive layer is good.

[Physical properties of peeling sheet]
＜ Temperature change of peeling force ＞
In one aspect of the present invention, the change rate of the peeling force before and after heating is preferably within ± 30%, more preferably within ± 25%, and even more preferably within ± 20%.
The change rate of the peeling force before and after heating can be measured by the following method.
The peeling force of the peeling sheet after 7 days of exposure in a high-temperature environment at a temperature of 70 ° C was set as the peeling force Y after heating.
The peeling force of the release sheet in a state not exposed in this high-temperature environment is referred to as an initial peeling force X.
In addition, from the measured peeling force Y after heating and the initial peeling force X, the rate of change in peeling force before and after heating can be calculated using the following formula.
Change rate of peeling force before and after heating = ((peeling force after heating Y-initial peeling force X) / initial peeling force X) × 100
The initial peeling force X was, of course, not exposed in a high-temperature environment at a temperature of 70 ° C. or exposed to other high-temperature environments, but was measured using a release sheet stored at room temperature after production.
The initial peeling force X and the post-heating peeling force Y can be measured by, for example, a method described in Examples described later. In addition, the change rate of the peeling force in the present invention is within ± Z%, which means that the change rate is (-Z%) or more (+ Z%) or less.

＜ Peeling force ＞
The optimal peeling force of the peeling sheet generally has various values depending on the applicable application or the type of the object to be laminated. There are cases where the peeling operation at the time of peeling is smooth and the lower peeling force is better, and in order to improve the object before the peeling operation. In the case where the material retention is high and the high peeling force is good.
The release sheet of the present invention is preferably used when the initial release force is set to be high.
In one aspect of the present invention, the peeling force of the peeling layer displayed by the peeling sheet is preferably 2500 mN / 20 mm or more, more preferably 3000 mN / 20 mm or more, and still more preferably 3500 mN / 20 mm or more. The upper limit of the peeling force of the peeling sheet is usually preferably 6000 mN / 20 mm.
In addition, since the peeling force of the peeling sheet varies depending on the object to be laminated, as an evaluation method thereof, it can be measured by a method described in Examples described later.

[Use of peeling sheet]
The release sheet of the present invention can be used as a protective sheet for various kinds of adhesives such as adhesive sheets, for example, it is used by being adhered to the surface of the adhesive layer side of the adhesive sheet having a substrate and an adhesive layer provided on one surface of the substrate. Moreover, it can also be used as a process film at the time of producing various resin sheets, ceramic green sheet, synthetic leather, various composite materials, etc. When used as a step film, it is used in the step of peeling various sheet materials formed by casting, coating resin, ceramic slurry, and the like on the surface of the release agent layer of the release sheet from the release sheet. Moreover, since the release sheet of this invention is formed from a non-silicone type | system | group release agent composition, it is especially preferable when using it as an electronic device. For example, in the manufacturing steps of electronic parts such as relays, various switches, connectors, motors, hard disks, etc., it can be used as a peeling sheet for adhesive sheets such as temporary fixation of electronic parts during assembly or display of parts contents. use.

[Manufacturing method of release sheet]
The release sheet of the present invention can be cross-linked as a release layer by, for example, coating a release agent composition on at least one side of a substrate and performing heat treatment to cross-link the polybutadiene (A) and the melamine compound (B). Manufactured together.
The release agent composition may be in the form of a solution diluted with a diluting solvent as described above.

The heat treatment temperature is preferably 100 to 170 ° C, and more preferably 130 to 160 ° C. The heat treatment time is not particularly limited, but it is preferably 30 seconds to 5 minutes.

Examples of the coating method of the release agent composition include, for example, a gravure coating method, a bar coating method, a spray coating method, a spin coating method, an air knife coating method, a roll coating method, a blade coating method, and a gate roller. Coating method, die coating method, and the like.

The coating thickness of the release agent composition is such that the thickness of the obtained release layer is adjusted to the above range.

[Example]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples.

The physical property values in the following examples and comparative examples are values measured by the following methods.

[Peel layer thickness]
The thickness of the peeling layer was measured using a spectroscopic ellipsometer (manufactured by JA Woollam Japan Co., Ltd., trade name: spectroscopic ellipsometer 2000U).

[Examples and Comparative Examples]
The release sheets of Examples 1 to 9 and Comparative Examples 1 to 4 were produced in the following order.

<Example 1>
As the polybutadiene (A) system, polybutadiene (A1) (manufactured by Soda Co., Ltd., trade name: GI-2000, bromine value: 8g / 100g, solid content concentration: 100% by mass, and number average molecular weight) : 2000).
Polybutadiene (A1) is a hydrogen addition to polybutadiene having hydroxyl groups only at both ends of the main chain. It is composed of 1,4-cis, 1,4-trans, and 1,2-vinyl. The ratio (cis / trans / 1,2-vinyl) is 0/15/85 in molar ratio.
As the crosslinking agent, hexamethoxymethylmelamine (manufactured by CYTEC INDUSTRIES, Japan, product name: CYMEL 303 (trade name), solid content concentration: 100% by mass) was used as a melamine compound.
As the acid catalyst, p-toluenesulfonic acid was used.

About 90 parts by mass of polybutadiene (A1), 10 parts by mass of a crosslinking agent and 2.0 parts by mass of p-toluenesulfonic acid were added to obtain a release agent composition. In addition, the "mass part" as used herein means a mass part converted by an active ingredient (solid content), and unless otherwise specified, it has the same meaning.
The p-toluenesulfonic acid is diluted with a mixed solvent of methanol and isopropanol (mass ratio 41.2: 9.4) to a solution having a solid content concentration of 50% by mass and added.
The obtained stripper composition was diluted to a solid content concentration of 2.5% by mass using a mixed solvent of toluene and methyl ethyl ketone (mass ratio 6: 4), and was formed into a solution form to prepare a coating liquid for the stripper composition.

The coating liquid of the obtained release agent composition was coated on one side of polyethylene terephthalate (manufactured by Mitsubishi Chemical Corporation, product name: DIAFOIL T-100) using a Maya rod to form a coating film. .
Next, the coating film was dried at 150 ° C. for 1 minute and hardened to form a peeling layer having a thickness of 150 nm to obtain a peeling sheet.

<Example 2>
A peeling sheet was obtained in the same manner as in Example 1 except that the blending ratio of polybutadiene (A1) and the crosslinking agent was changed, and 50 parts by mass of the crosslinking agent was added to 50 parts by mass of the polybutadiene (A1).

<Example 3>
A peeling sheet was obtained in the same manner as in Example 1 except that the blending ratio of polybutadiene (A1) and the crosslinking agent was changed, and 90 parts by mass of a crosslinking agent was added to 10 parts by mass of polybutadiene (A1).

<Example 4>
Instead of using polybutadiene (A1) instead of polybutadiene (A2) (manufactured by Soda Co., Ltd., trade name: GI-1000, bromine value: 7g / 100g, solid content concentration: 100% by mass, number average Except for molecular weight: 1,500), a release sheet was obtained in the same manner as in Example 1.
Polybutadiene (A2) is the same as polybutadiene (A1). It is a hydrogen addition to polybutadiene with hydroxyl groups at both ends of the main chain. 1,4-cis, 1,4-trans The composition ratio (cis / trans / 1,2-vinyl) of 1,2-vinyl is 0/15/85 in molar ratio. However, the number average molecular weight and bromine value are different from those of polybutadiene (A1).

<Example 5>
Instead of using polybutadiene (A1) instead of polybutadiene (A3) (manufactured by Soda Co., Ltd., trade name: GI-3000, bromine value: 13g / 100g, solid content concentration: 100% by mass, number average Except for molecular weight: 3,100), a release sheet was obtained in the same manner as in Example 1.
Polybutadiene (A3) is the same as polybutadiene (A1) and (A2). It is a hydrogen addition of polybutadiene with hydroxyl groups only at both ends of the main chain. 1,4-cis isomers, 1,4 The composition ratio (trans / trans / 1,2-vinyl) of the trans-isomer and 1,2-vinyl is 0/15/85 in molar ratio. However, the number average molecular weight and bromine value are different from those of polybutadiene (A1) and (A2).

<Example 6>
Instead of using polybutadiene (A1) instead of polybutadiene (A4) (manufactured by Soda Co., Ltd., trade name: GI-1000, bromine value: 400g / 100g, solid content concentration: 100% by mass, number average Except for molecular weight: 1,400), a release sheet was obtained in the same manner as in Example 1.
Polybutadiene (A4) is the same as polybutadiene (A1) ~ (A3). It is a hydrogen addition of polybutadiene with hydroxyl groups only at both ends of the main chain. 1,4-cis isomer, 1,4 The composition ratio (trans / trans / 1,2-vinyl) of the trans-isomer and 1,2-vinyl is 0/15/85 in molar ratio. However, the difference from polybutadiene (A1) to (A3) is that it is not hydrogenated. The number average molecular weight and bromine value are different.

<Example 7>
A peeling sheet was obtained in the same manner as in Example 1 except that polybutadiene (A), and polybutadiene (A ') different from polybutadiene (A) were prepared, and the blending ratio of each component was changed.
The polybutadiene (A) is a polybutadiene (A1).
Polybutadiene (A ') is polybutadiene (A4).
The blending of each component is as follows.
45 parts by mass of polybutadiene (A1), 45 parts by mass of polybutadiene (A4), 10 parts by mass of melamine compound, and 2.0 parts by mass of p-toluenesulfonic acid.

<Example 8>
The blending ratio of polybutadiene (A1), polybutadiene (A4), and cross-linking agent was changed. For polybutadiene (A1) 10 parts by mass, polybutadiene (A4) was set to 10 parts by mass, and melamine Except for the compound being 80 parts by mass, a peeling sheet was obtained in the same manner as in Example 7.

<Example 9>
Instead of polybutadiene (A4), polybutadiene (A5) (manufactured by Idemitsu Kosan Co., Ltd., trade name: poly bd R-45HT, bromine value: 398g / 100g, solid content concentration: 100% by mass Except for the number average molecular weight: 2,800), a peeling sheet was obtained in the same manner as in Example 7.
Polybutadiene (A5), like polybutadiene (A4), is a polybutadiene having hydroxyl groups only at both ends of the main chain, without being hydrogenated. However, the composition ratios (cis / trans / 1,2-vinyl), number average molecular weight, and bromine value of 1,4-cis isomer, 1,4-trans isomer, and 1,2-vinyl are different.
Composition ratio of 1,4-cis, 1,4-trans, and 1,2-vinyl of polybutadiene (A5) (cis / trans / 1,2-vinyl) The ear ratio is 20/60/20.

〈Comparative example 1〉
A release sheet was obtained in the same manner as in Example 1 except that polybutadiene (A1) was used instead of polybutadiene (A5).

〈Comparative example 2〉
Instead of polybutadiene (A1), polybutadiene (A6) was used (manufactured by EVONIK, trade name: polyvest 110, bromine value: 400 g / 100 g, solid content concentration: 100% by mass, number average molecular weight: 1,000) Other than that, a release sheet was obtained in the same manner as in Example 1.
Polybutadiene (A6) is a polybutadiene which has no hydroxyl group and is not hydrogenated.
In addition, the composition ratio of the 1,4-cis isomer, 1,4-trans isomer, and 1,2-vinyl isomer of polybutadiene (A6) (cis / trans / 1,2-vinyl), 75/24/1 in mole ratio.

〈Comparative example 3〉
Instead of polybutadiene (A1), polybutadiene (A7) was used (manufactured by EVONIK, trade name: polyvest HT, bromine value: 400 g / 100 g, solid content concentration: 100% by mass, number average molecular weight: 2,900) Other than that, a release sheet was obtained in the same manner as in Example 1.
Polybutadiene (A7) is the same as polybutadiene (A4) and (A5), but it is a polybutadiene having hydroxyl groups at both ends only, without being hydrogenated. However, the composition ratios (cis / trans / 1,2-vinyl), number average molecular weight, and bromine value of 1,4-cis isomer, 1,4-trans isomer, and 1,2-vinyl are different.
Composition ratio of polybutadiene (A7) 1,4-cis, 1,4-trans and 1,2-vinyl (cis / trans / 1,2-vinyl) The ear ratio is 20/58/22.

〈Comparative example 4〉
Instead of using a melamine compound as a cross-linking agent, an isocyanate compound (manufactured by Japan Polyurethane Co., Ltd., trade name: CORONATE L, solid content concentration: 75% by mass, and diluent solvent: ethyl acetate) was used. In the same manner as in Example 1, a release sheet was obtained.

The peeling sheets of Examples 1 to 9 and Comparative Examples 1 to 4 were subjected to the following measurements and evaluations.

[Evaluation of peeling force]
On the release layer of the release sheets of Examples 1 to 9 and Comparative Examples 1 to 4, a 20-mm-wide adhesive tape (manufactured by Nitto Denko Corporation, product number: No. 31B) was attached using a 5 kg roller to produce a peel force measurement. With samples.
After being attached for 30 minutes, the obtained sample was fixed on a universal tensile tester (manufactured by Shimadzu Corporation, trade name: AUTOGRAPH AGS-20NX) in accordance with JIS K6854-1999 at a tensile speed of 0.3 m / min. The peeling force (mN / 20mm) of the release sheet was measured by peeling the adhesive tape from the release layer in a 180 ° direction.
The peel force measurement of the peeling sheets of Examples 1 to 9 and Comparative Examples 1 to 4 was performed before and after exposure to a high temperature environment at a temperature of 70 ° C for 7 days.
Next, the peeling force of the peeling sheet after being exposed to the high temperature environment for 7 days is set to the peeling force Y after heating, and the peeling force of the peeling sheet in a state not exposed to the high temperature environment is set to the initial peeling force X, which is calculated using the following formula: Change in peel force before and after heating.
Change rate of peeling force before and after heating = ((peeling force after heating Y-initial peeling force X) / initial peeling force X) × 100

[Evaluation of Solvent Resistance]
On the release layers of the release sheets of Examples 1 to 9 and Comparative Examples 1 to 4, a non-woven cloth (made by Asahi Kasei Corporation, trade name: BEMCOTON) impregnated with methyl ethyl ketone was placed, and wiped 5 times with a load of 100 g from above. The surface of the release layer was visually observed. When the surface of the release layer was not changed, it was evaluated as ○, and when the surface of the release layer was whitened due to a flaw or the like, it was evaluated as ×.

The results are shown in Table 1.
In Table 1, "Bd-H" described in the composition column means a hydrogen additive of polybutadiene, and "Bd" means a non-hydrogen additive of polybutadiene.
In Table 1, "OH" described in the functional group column means polybutadiene having hydroxyl groups only at both ends of the main chain, and "none" means polybutadiene having no hydroxyl groups.

As can be seen from Table 1, it is as follows.
Self-contained release agent composition containing polybutadiene (A) and melamine compound with a crosslinkable functional group and 50 mol% or more of vinylene based on all constituent units of polybutadiene as a basis The peeling sheet of Examples 1 to 9 of the formed peeling layer had very little change in the peeling force before and after heating. It can be seen that the rate of change in the peeling force before and after heating was limited to within ± 30%. Moreover, it turns out that the release layer of the release sheets of Examples 1 to 9 is also excellent in solvent resistance.
In addition, the peeling force of the peeling sheets of Examples 1 to 9 was 2500 mN / 20 mm or more before and after heating. It can be seen that the initial peeling force is changed to a relatively high value, and the stability over time at high temperatures is still excellent.
On the other hand, the peeling sheet of Comparative Examples 1 to 3 of polybutadiene whose content ratio of 1,2-vinyl is less than 50 mol% based on the total constituent units of polybutadiene was used. The peeling force varies greatly, and it can be seen that the peeling force significantly increases after heating.
In addition, Comparative Example 2 using polybutadiene having no crosslinkable functional group instead of polybutadiene (A) having a crosslinkable functional group, and peeling of Comparative Example 4 using an isocyanate compound instead of a melamine compound. Compared with the release layers of the release sheets of Examples 1 to 9, the release layer of the sheet was found to have insufficient solvent resistance, and the strength of the film was poor in order to evaluate the degree of the release force.

1‧‧‧ peeling sheet

10‧‧‧ Substrate

11‧‧‧ peeling layer

FIG. 1 is a schematic cross-sectional view of a release sheet according to an aspect of the present invention.

Claims (5)

A release sheet, which is a release sheet having a substrate and a release layer, The release layer is a layer formed of a release agent composition containing a polybutadiene (A) having a crosslinkable functional group and a melamine compound (B), The crosslinkable functional group is a functional group that reacts with the melamine compound (B), The polybutadiene (A) having a crosslinkable functional group includes 50 mol% or more of 1,2-vinyl based on all the constituent units of the polybutadiene (A). The release sheet according to claim 1, wherein the crosslinkable functional group is a hydroxyl group. The release sheet according to claim 1 or 2, wherein the polybutadiene (A) having a crosslinkable functional group is a hydrogen additive having a bromine value of 10 g / 100 g or less. The peeling sheet according to any one of claims 1 to 3, wherein the peeling force of the aforementioned peeling sheet after 7 days of exposure to a high temperature environment of 70 ° C. is set as the peeling force Y after heating, and is not exposed to the aforementioned When the peeling force of the aforementioned release sheet in a state in a high-temperature environment is an initial peeling force X, a change rate represented by {(peeling force after heating Y-initial peeling force X) / initial peeling force X} × 100 is ± 30% Within. If the peeling sheet according to any one of claims 1 to 4, the peeling force when peeling from the adhesive layer is 2500 mN / 20 mm or more.