JPH02214624A - Mold release film - Google Patents

Abstract

PURPOSE:To enhance the mold release characteristics, heat resistance, durability and nontransferability by providing the cured thin film of a specified silane coupling agent on single side or double sides of a polyester film. CONSTITUTION:The cured thin film of a silane coupling agent shown in a general formula YR1Si(OR)3 (wherein R shows methyl group or ethyl group, R1 shows lower alkylene group, Y shows organic functional group) is provided on single side or double sides of a polyester film. The silane coupling agent is made aqueous liquid and it is preferable that the silane coupling agent is partially hydrolyzed and thereafter utilized. The cured thin film is formed by applying this aqueous liquid to single side or double sides of the polyester film and furthermore performing heat-treatment. The aqueous solvent is removed by this heat-treatment and curing reaction (self-condensation reaction) of partial hydrolysate is progressed. The treatment temp. is preferably regulated to 180 deg.C or more from the viewpoint of curing reactivity. In such a way, when the cured thin film of the silane coupling agent is provided on the polyester film, mold release characteristics for vinyl chloride resin can be imparted to this film.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a release film, and more specifically, a polyvinyl chloride resin film or sheet (hereinafter, these may be simply referred to as a film) by a casting method. The present invention relates to a release film that is used when manufacturing the film and has excellent release properties, heat resistance, durability, non-transferability, etc. from the film.

[Prior Art] It is known to produce a film of vinyl chloride resin by a casting method. This casting method basically consists of casting an emulsion or solution of vinyl chloride resin from a die onto a release paper, drying off the solvent, and then peeling the formed film from the release paper, but conventional The release paper has disadvantages of poor surface smoothness, solvent resistance, heat resistance, etc.

On the other hand, polyester films have excellent physical, chemical, and thermal properties and are used for various purposes, one of which is release films. Polyester release film is used, for example, to protect the curing reactivity and moldability of curable resins such as urethane resins, epoxy resins, and unsaturated polyester resins, and can be used for practical release without special surface treatment. It is known to exhibit sexual characteristics.

However, according to the research results of the present inventors, even if a polyester film is used instead of the release paper, the adhesion between the polyester film and the vinyl chloride resin is large, and the film acts as a release film for vinyl chloride resin casting. It became clear that it was not possible. Furthermore, even if a polyester film is provided with a thin film (release layer) made of a cured product of silicone oil having a vinyl siloxane group, a repelling phenomenon due to the silicone will occur, causing serious damage to the surface of the vinyl chloride resin film after release from the mold. It has become clear that there are some drawbacks. Furthermore, the curing reaction of silicone oil is slow,
It has also become clear that under normal film processing conditions, the reaction cannot be completed completely, and that the monomer silicone oil is transferred to the mold release surface, causing problems in post-processing.

[Purpose of the Invention] The present inventor has conducted further research in order to improve the above drawbacks and develop a release film useful for manufacturing vinyl chloride resin films by a casting method, and as a result, has arrived at the present invention. .

An object of the present invention is to provide a release film for vinyl chloride resin casting that has excellent mold release properties, heat resistance, durability, non-transferability, etc. and is useful for producing a vinyl chloride resin film with a smooth surface.

[Structures and Effects of the Invention] According to the present invention, the general formula YRs Si is formed on one or both sides of the polyester film.
(OR)! (Here, R is a methyl group or an ethyl group, R1 is a lower alkylene group, and Y is an organic functional group)
This is achieved by a flying mold film for vinyl chloride resin casting, which is provided with a cured thin film of a silane coupling agent represented by:

The polyester in the present invention is a crystalline linear saturated polyester produced from an aromatic dibasic acid or its ester-forming derivative and a diol or its ester-forming derivative, and specifically, polyethylene terephthalate, polypropylene terephthalate, etc. Preferred examples include polybutylene terephthalate, polyethylene-2,6-naphthalate, and poly(1,4-cyclohexylene dimethylene terephthalate). Further, a copolymer in which some of these components are substituted with other components, a mixture with polyalkylene glycol or other resins may be used.

The polyester film of the present invention can be produced by a conventionally known method. For example, the polyester is dried, then melted, extruded from a die (for example, T die, ■ die, etc.) onto a cooling drum, and then rapidly cooled to form an unstretched film. It can be produced by biaxially stretching the unstretched film and further heat-setting it. The thickness of the film is
Although there is no particular limitation, the thickness is preferably 12 to 250 μm. As a polyester film, a film that does not contain a lubricant is preferable in terms of surface flatness, but in order to control surface roughness, a film that does not contain a lubricant,
For example, it may be a film containing inorganic fine particles such as calcium carbonate, kaolin, silica, titanium oxide, etc. and/or precipitated fine particles of catalyst residue, or an antistatic color tone adjusting agent such as sodium dodecylbenzenesulfonate. The film may also contain other additives such as.

In the present invention, the cured thin film provided on one or both sides of the polyester film is a cured thin film of a silane coupling agent. This silane coupling agent is a compound represented by the following general formula % (where R is a methyl group or an ethyl group + R1 is a lower alkylene group, and Y is an organic functional group). In the above general formula, the lower alkylene group for R1 is particularly preferably a propylene group, and the organic functional group for Y is particularly preferably an amino group or a glycidyl group. The above amino group is N-β (aminoethyl)
It is to be understood that substituted amino groups such as amino groups [R2NCH2CH2-NH] are included. Specific examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyltriethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N- Preferable examples include β(aminoethyl)γ-aminopropyltrimethoxysilane. These can be used alone or in combination of two or more.

The silane coupling agent is preferably used as an aqueous liquid and partially hydrolyzed, and a cured thin film can be formed by applying the aqueous liquid to one or both sides of a polyester film and further performing a heat treatment. By this heat treatment, the water solvent is removed and the curing reaction (self-condensation reaction) of the partial hydrolyzate proceeds. The treatment temperature is preferably 180° C. or higher from the viewpoint of curing reactivity.

The aqueous silane coupling agent may be applied in a normal coating process, that is, in a process in which it is applied to a biaxially stretched and heat-set polyester film separately from the film manufacturing process.However, in this process, dirt, dust, etc. Coating in a clean atmosphere is preferred. From this point of view, it is preferable to apply during the polyester film manufacturing process. Particularly, during this process, before crystal orientation is completed, aqueous coating is applied to one or both sides of the polyester film. It is preferable to apply a coating liquid.

Here, the polyester film before crystal orientation is completed is an unstretched film obtained by thermally melting polyester and forming it into a film as it is; A uniaxially stretched film that is oriented in one direction; and a film that is oriented by stretching at a low magnification in both the longitudinal and transverse directions (before finally being re-stretched in the longitudinal or transverse direction to complete oriented crystallization). biaxially stretched film).

The solid content concentration of the coating liquid is usually 30% by weight or less, more preferably 10% by weight or less.
．． is preferred.

As the coating method, any known coating method can be applied6.
For example, roll coating method, gravure coating method, roll plush method, spray coating method, air knife coating method,
It is preferable to apply an impregnation method, a curtain coating method, etc. alone or in combination.

A polyester film coated with a coating liquid and before completion of crystal orientation is dried and subjected to processes such as stretching and heat setting.6 For example, a vertically-axially stretched polyester film coated with an aqueous liquid is guided to a stenter and then stretched horizontally. Stretched and heat set. During this time, the coating solution is dried and thermally cured.

Oriented crystallization conditions of polyester film, e.g. stretching,
Conditions such as heat fixation can be carried out under conditions conventionally known to those skilled in the art.

Such an aqueous liquid can be used by adding a necessary amount of a surfactant such as an anionic surfactant, a cationic surfactant, or a nonionic surfactant.

As such a surfactant, the surface tension of the aqueous coating solution is 40
Those that can reduce the dyne/ai+ and promote wetting to polyester films are preferred, such as polyoxyethylene alkyl phenyl ether.

Polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester.

Examples include fatty acid metal soaps, alkyl sulfates, alkyl sulfonates, alkyl sulfosuccinates, quaternary ammonium chloride salts, and alkylamine hydrochloric acids. Further, other additives such as antistatic agents, ultraviolet absorbers, IL additives, organic fillers, inorganic fillers, lubricants, antiblocking agents, etc. may be mixed within a range that does not eliminate the effects of the present invention.

Although the cause of the release effect of the cured thin film formed by the above method (m-type layer) is not known in detail, it is presumed as follows. The critical surface tension (γC) of vinyl chloride resin and polyester film is about 39 and 43 dvn/, respectively.
It is csa. Further, for example, the γC of the surface of a polyester film coated with γ-glycidoxypropyltrimethoxysilane and dried is about 50 den/am. Therefore, the difference in γC at the interface between the vinyl chloride resin and the cured thin film of the silane coupling agent is larger than the difference in γC at the interface between the vinyl chloride resin and the polyester.The larger the difference in γC, the worse the adhesion. Therefore, by providing a cured thin film of a silane coupling agent on a polyester film, it is possible to impart mold release properties to vinyl chloride resin to the polyester film.

The release film of the present invention has excellent mold releasability against vinyl chloride resin, and also has excellent heat resistance, durability, non-transferability, and surface smoothness, so it has the disadvantages of conventionally used release paper. This method has the advantage of being able to solve the problem, improve the casting properties of vinyl chloride resin, and produce a single sheet of vinyl chloride resin film with excellent surface properties.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, "parts" in the examples indicate "parts by weight", and the releasability, transferability, and durability of the coating layer were determined by the following methods.

Tog-type coating surface is coated with vinyl chloride emulsilane (Nippon Zeon G-576) and dried to form a vinyl chloride thin film with a thickness of 1 μm. A 18-width cellophane tape was pressed onto this with a rubber roll, and the thin film was peeled off in the 180°C direction using an Instron tensile tester.The peel resistance value between the vinyl chloride thin film and the coating surface (g/181111)
).

(2) Transferability The surface in contact with the coated surface of the vinyl chloride thin film piece whose mold releasability was examined using the method described in (1) above was subjected to X-ray microanalysis, and judgment was made based on the presence or absence of an SL fluorescence X-ray peak.

(3.Durability) Perform the test in (1) above 5 times on the same coating surface, and if the peeling load is 50g / 18+n+ or less, it is good (0
).

Examples 1-3 Intrinsic viscosity measured in O-chlorophenol at 35°C 0
．． 65 polyethylene terephthalate 1- (lubricant 500
ppl (containing ppl) was melt-extruded onto a rotating cooling drum maintained at 20°C to obtain an unstretched film with a thickness of 950 μm, and then stretched 3.5 times in the machine axis direction (* direction). 90 parts of ring agent component and 10 parts of nonionic surfactant (polyoxyethylene nonylphenyl ether)
An aqueous solution containing 10% of the total amount was applied to one side of a uniaxially stretched film by a kiss coating method. Subsequently, the film was stretched 3.9 times in the transverse direction at 105°C and further heat-treated at 210°C to obtain a polyester film coated with a release layer (1!I type film) having a thickness of 75 μm.

The release characteristics of this film are shown in Table 1.

Comparative Example 1 A polyester film was obtained in the same manner as in Example 1 except that the application of the aqueous liquid was omitted. This polyester film was not subjected to any surface treatment.

The release characteristics of this film are shown in Table 1.

As is clear from Table 1, the release film of the present invention has no crushing or transferability in releasability against vinyl chloride, and is a durable film.

Claims (1)

[Claims] 1. On one or both sides of the polyester film, a compound represented by the general formula YR_1Si(OR)_3 (where R is a methyl group or an ethyl group, R_1 is a lower alkylene group, and Y is an organic functional group) is used. A release film for vinyl chloride resin casting, which is provided with a cured thin film of a silane coupling agent. 2. The release film according to claim 1, wherein the organic functional group Y in the general formula is an amino group or a glycidyl group. 3. The cured thin film according to claim 1 or 2, wherein the cured thin film is formed by applying a partial hydrolyzate of a silane coupling agent to one or both sides of a polyester film, and then performing a heat curing treatment at 180°C or higher. Release film.