JPH03120042A - Mold release film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a release film, and more specifically, a release layer using polyvinyl alcohol or polyethyleneimine having an alkyl group in the side chain is attached to a polyester film with excellent adhesion. The present invention relates to a release film that is formed by laminating layers and has excellent durability and release properties.

The conventional pattern film is used for the purpose of protecting the adhesive surface made of adhesives, adhesives, etc., or as a support when producing sheets of vinyl chloride, polyurethane, etc., or for reactive curable resins such as polyurethane resin, epoxy resin, etc. .

It is used for the purpose of protecting the curing reaction and moldability of unsaturated polyester resins, and its amount is increasing.

As such a release film, a polyester film having a coating made of a cured silicone oil on at least one surface has conventionally been used. This cured product has the advantages of being non-adhesive, having excellent mold release properties, and having excellent thermal stability. However, the v! of polyester film and silicone oil cured film! ! Adhesion was insufficient, and because the silicone oil was not sufficiently cured, uncured silicone oil could be transferred to the other side or the back of the polyester film, which could adversely affect subsequent processing. be.

On the other hand, polyvinyl alcohol or polyethyleneimine, which have an alkyl group in the side chain, are known as non-silicone mold release agents, and these are used for paper.

Polyethylene film, polypropylene film (OP
It is coated on the surface of P film), cellophane, etc., and used for back side treatment of adhesives, release paper for adhesives, marking films, etc.

When this non-silicone mold release agent is applied to a polyester film, it has a drawback in adhesion. In other words, vinyl chloride resin does not pose a particular problem when used only once, such as to protect adhesive products.

When mold release is repeated, such as with a mold release film when manufacturing resin molded products such as urethane resin or acrylic resin, the mold release layer peels off or is missing due to poor adhesion.

Purpose of the Invention As a result of intensive research in order to resolve the lack of appetizing properties in overcoating, the present inventor has developed an i
providing a coating on at least one surface of the polyester film;
It was discovered that when the above-mentioned mold release agent layer is provided on top of the mold release agent layer, a mold release film that can be used repeatedly can be obtained, and the present invention has been achieved.

Therefore, an object of the present invention is to provide a release film that has excellent durability and can be used repeatedly.

Structure/Effects of the Invention According to the present invention, an undercoat layer using a silane coupling agent is provided on at least one surface of a polyester film, and a polyvinyl alcohol or polyethylene film having an alkyl group in the side chain is applied thereon. This is achieved by a release film provided with a release layer using imine.

The polyester in the present invention is a linear saturated polyester produced from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, and specifically includes polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate. ,
Examples include polyethylene 2,6-naphthalate.

In addition, copolymers in which some of these components are substituted with other components,
It may also be a polyalkylene glycol or a mixture with other resins.

The polyester film in the present invention can be manufactured by a conventionally known method.

For example, the above-mentioned polyester is dried and then melted, extruded from a die (e.g., T-die, I-die, etc.) onto a cooling drum, rapidly cooled to obtain an unstretched film, and then the unstretched film is stretched vertically by 2 to 4 mm. It can be produced by stretching twice, stretching 2 to 4 times in the transverse direction, and further heat-setting at 180 to 220°C. There is no particular limit to the film thickness, but it is between 5 and 25
0 μm is preferable.

As a polyester film, a film that does not contain a lubricant is preferable from the viewpoints of transparency and surface flatness, but from the viewpoint of film slipperiness and processability, a lubricant, such as inorganic fine particles such as calcium carbonate, kaolin, silica, titanium oxide, etc., is preferable. And/or it may be a film containing precipitated fine particles with residual catalyst, or a film containing an antistatic agent such as sodium dodecylsulfonate, and other additives such as a color tone adjusting agent. Also good.

Examples of the silane coupling agent for forming the undercoat layer in the present invention include vinyl ethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-aminopropylmethyljethoxysilane. Can be mentioned. The silane coupling agent is usually used as an aqueous solution at 11 degrees of 0.1 to 5.0%, and the coating amount on the surface of the polyester film is preferably 0.02 to 0.2 y/m (after drying). The silane coupling agent may be applied during the film forming process! mil! It may be done at a different location than the process. When carried out during the film forming process, unstretched film, -axially stretched film (
Especially longitudinally stretched film), biaxially stretched film, two-wheel stretched film,
It can be applied to films after heat setting. Among these, it is preferable to apply it to a longitudinally stretched film before being subjected to transverse stretching. Examples of coating methods include spin cord brushing and gravure coating.

Various coating methods such as a kiss coating method, a bar code method, and a reverse coating method can be used. Coating can be on one or both sides of the polyester film.

In the present invention, a mold release agent layer is provided on the undercoat layer.

The mold release agent layer contains polyvinyl alcohol or polyethyleneimine having an alkyl group in its side chain. This alkyl group preferably has 8 to 20 carbon atoms,
For example, octyl and nonyl.

Examples include decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, and the like. Such an alkyl group can be preferably introduced by reacting an alkyl isocyanate with polyvinyl alcohol or polyethyleneimine. In this reaction, the alkyl isocyanate reacts with the hydroxyl group of polyvinyl alcohol or the imine group of polyethyleneimine to introduce an alkyl group into the molecular chain. The modification with alkyl isocyanate is preferably carried out so that 50% or more of the hydroxyl groups or imine groups are reacted. Some commercially available products are 50-80% modified. As the proportion of alkyl groups introduced into molecular side chains (modification rate) increases, the peeling force decreases, which is favorable in terms of mold release performance, but the adhesion to the polyester film tends to decrease. In the present invention, since the surface of the polyester film is undercoated with a silane coupling agent, it is possible to eliminate the above-mentioned decrease in adhesion. can also be used.

Polyvinyl alcohol or polyethyleneimine having an alkyl group in its side chain is usually used after being dissolved in a solvent such as toluene or xylene at a concentration of about 0.5 to 5.0%. Examples of methods for applying the coating liquid include a spin code method, a gravure coating method, and a kiss coating method.

Various coating methods such as bar code method and reverse coating method can be used. As for the coating amount, the film thickness after drying is 0.
A thickness of 0.05 to 0.5 μm is preferable.

Drying after application is performed at a drying temperature of, for example, 80-1 to evaporate the solvent.
This can be done by passing through a drying oven at 00°C.

The release film of the present invention has a release layer containing polyvinyl alcohol or polyethyleneimine having an alkyl group in its side chain and is laminated with strong adhesion to the surface of the polyester film via an undercoat layer, resulting in excellent release properties. It also has the characteristic that the release layer does not peel off or chip even after repeated use, and is particularly suitable for use as a support when manufacturing sheets such as vinyl chloride and polyurethane, or reactive curable resins such as polyurethane. It is useful as a material that protects the curing reaction and moldability of resins, epoxy resins, unsaturated polyester resins, etc.

Example Hereinafter, the present invention will be explained in more detail with reference to Examples.

Note that various properties of the release film were measured by the following methods.

1) Peeling force of cellophane tape (initial) Press adhesive cellophane tape with a width of 24 mm onto the coating surface with a rubber roll, and test it with an Instron type tensile tester at 1
Peeling occurs in the 80° direction, and the resistance value at this time is shown.

2) Repeated peeling force of t70 cellophane tape (repeated 10 times) Cellophane tape was peeled off repeatedly at the same location on the film 10 times, and the value of the peeling force with respect to the initial value is expressed as a percentage.

3) Urethane resin release (initial stage) A urethane emulsion (Merci 545 manufactured by Toyo Polymer Co., Ltd.) was coated on the surface of the release film and dried at 120°C to form a urethane film having a thickness of about 35 μm after drying.

This urethane coating film was tested using an Instron type tensile tester.
Peeling occurs in the 0° direction, and the resistance value at this time is shown.

4) Repeated release of urethane resin (repeated 10 times) The formation and peeling of the urethane resin film was repeated 10 times on the same release film surface, and the change in release force with respect to the initial value is expressed as a percentage.

Comparative Example 1 Molten polyethylene terephthalate ([η]-0,65)
is extruded from a die and quenched in close contact while applying an electrostatic charge on a cooling drum maintained at about 40°C to obtain a film.Then, the film is enlarged by 3.6 times in the longitudinal direction and then by 3 times in the transverse direction.
．． Stretched 7 times, then heat set at 235℃ to 50
A two-wheel stretched polyester film with a thickness of μm was obtained.

Next, polyvinyl alcohol and pentadecyl isocyanate were reacted, and a compound in which 75% of the total number of functional groups (-OH) were modified with pentadecyl groups (Asio Sangyo Asio Resin RA-95) was dissolved in toluene at a concentration of 1.0% by weight. The solution was applied to the surface of the polyester film using a Mayer bar at a coating amount of 10 g/TIL, and dried at 120°C to obtain a release film. Table 1 shows the release performance of this release film.

Comparative Example 2 A compound (Nippon Shokubai Chemical Co., Ltd., trade name RP- 20)
A toluene solution containing 1.0% by weight of 1.0% by weight was applied using a Mayer bar so that the coating amount was 109/m, and then dried at 120°C to obtain a release film. Table 1 shows the release performance of this release film.

Example 1 Molten polyethylene terephthalate ([η]=0.65
) is extruded from a die and brought into close contact with a rotating cooling drum maintained at approximately 40°C while applying electrostatic charge.

A film is obtained by rapid cooling, and then the film is rolled vertically for 3
．． After stretching 6 times, an aqueous solution containing 90 parts by weight of γ-glycidoxypropylmethyljethoxysilane and 10 parts by weight of a nonionic surfactant (polyoxyethylene nonylphenyl ether) was coated on one side of the longitudinally stretched film using a kiss coating method. Coated. Next, the film was stretched 3.7 times in the transverse direction at 105°C and further heat-set at 235°C to obtain a subbed-treated film with a thickness of 50 μm.

A toluene solution of Asioresin RA-95 used in Comparative Example 1 was applied to the undercoat layer surface of this undercoat film using a Mayer bar so that the coating amount was 10 g/Td.
A release film was obtained by drying at 20°C. Table 1 shows the release performance of this release film.

Table 1 Example 2 A longitudinally stretched film was obtained in the same manner as in Example 1, and then an aqueous solution containing 90 parts by weight of vinyltriethoxysilane and 10 parts by weight of a nonionic surfactant was applied to the longitudinally stretched film using a kiss coating method. It was applied to one side of the film.

Next, it was stretched 3.7 times in the transverse direction at 105°C, and further stretched to 235°C.
Heat setting was carried out at 0.degree. C. to obtain an undercoated film having a thickness of 50 .mu.m.

On this undercoated film surface, the RP-
20 toluene solution with a Mayer bar, the application amount is 1.
It was coated to give a coating weight of 0 g/Td and dried at 120° C. to obtain a release film. The release performance of this release film is shown below.
Shown in 1.

From the above table, it can be seen that the release films of Examples have excellent durability and excellent template performance even when used repeatedly.

Claims (1)

[Claims] 1. An undercoat layer using a silane coupling agent is provided on at least one surface of the polyester film, and a release layer using polyvinyl alcohol or polyethyleneimine having an alkyl group in the side chain is provided thereon. Release film. 2. The release film according to claim 1, wherein the alkyl group has 8 to 20 carbon atoms. 3. The release film according to claim 1 or 2, wherein the alkyl group is introduced by a reaction between an alkyl isocyanate and polyvinyl alcohol or polyethyleneimine.