JPS5826379B2 - Temporary adhesive masking film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synthetic resin masking film that is temporarily attached to the surface of an adherend (for example, a metal plate or an aluminum plate) during processing.

Masking film is temporarily attached to one or both sides of a stainless steel plate, aluminum plate, colored steel plate, etc., and serves to protect the surface from damage or contamination during transportation or handling of the adherend. It is also used to prevent damage to the surface of aluminum plates, etc. caused by pressing dies during press processing, roll homing, etc., and is ultimately peeled off and removed at the end user stage (hereinafter referred to as practical use). The film is required to be able to be easily peeled off from the adherend, and to have a strong temporary adhesion, but to be free from contamination caused by the masking film when peeled off.

Currently, masking films are based on polyvinyl chloride or polyethylene films, and are coated with adhesives used in general adhesive tapes (for example, adhesives mainly composed of ethylene-vinyl acetate copolymers and acrylic esters). ) are often used.

With conventional masking films, the adhesive strength increases over time due to the action of ultraviolet rays or heat after masking, making it impossible to remove in practical use, or even if it is possible to remove it, some of the adhesive remains on the adherend. There are disadvantages such as residual residue contaminating the surface, and the adhesive strength gradually decreases due to moisture and the masking effect disappears.

In addition to the above-mentioned drawbacks, conventional masking films also have the drawback that after the first deep drawing process, the film lifts up, making it impossible to perform the second and third deep drawing processes, making it difficult to make stainless steel bathtubs and sinks. It has not been put to practical use in applications such as deep drawing of metal plates in several stages, as in the case.

As a result of intensive studies to solve the problems of conventional masking films, the inventors of the present invention discovered that a temporary adhesive masking film containing a silane compound is superior. Patent application (Patent application Sho-51-9)
However, as a result of continuing research to obtain a masking film that is even more suitable for low temperatures than the present invention, the present inventors applied a mixture of a silane compound and a urethane oligomer to the film surface to increase the temperature from room temperature to the resin melting temperature. It was possible to obtain a film with excellent masking properties in the temperature range of 50°C to 100°C.

That is, the present invention is a temporary adhesion masking film characterized by applying a mixture of a silane compound and a urethane oligomer to the surface of a synthetic resin film.

The silane compound used in the present invention refers to an organic silane compound having two or more different reactive groups in its molecule.

One of the two reactive groups is a reactive group (e.g. methoxy group, ethoxy group, silanol group, chloro group, acetoxy group, β-methoxy group, t -butyl-peroxy group) and the other reactive group is a reactive group that forms a bond with the synthetic resin film as a substrate (e.g. vinyl group, octoxy group, glycidyl group,
(mercapto group, epoxy group, amino group) are preferred.

Examples of such silane compounds include N-β-aminopropyl-γ-aminopropyltrimethoxysilane, vinylchlorosilane, and vinyltrissilane.

Moreover, the urethane oligomer used in the present invention has a molecular weight of 4
00 to 10,000 polymer diol (hereinafter referred to as polymer diol) and a polyfunctional chain extender (hereinafter referred to as chain extender) are mixed in a molar ratio of 1:0.5 to 1:10. It is an isocyanate-terminated urethane oligomer obtained by reacting an organic diisocyanate (hereinafter referred to as diisocyanate) with an active hydrogen group and an isocyanate group at an equivalent ratio of 1=1.05 to 1:1.80. .

Examples of high molecular diols include polyether diol, polyester diol, polycaprolactone diol, etc., and examples of chain extenders include low molecular diols (ethylene glycol, flopylene gelylcol, 1,4-butanediol, neopentyl glycol, methylolpropane, etc.), low-molecular diamines, and low-molecular amino alcohols.

Further, as the diisocyanate, either aromatic or aliphatic diisocyanate can be used.

The base material for the synthetic resin film used in the present invention is a thermoplastic resin, preferably polyvinyl chloride, polyethylene, ethylene-vinyl acetate copolymer, or the like.

In order to obtain the film of the present invention, the silane compound and urethane oligomer are mixed at a mixing ratio of 1:0.1 to 1:100, particularly preferably 1:0.5 to 1:1O, and this mixture is mixed at 0.01 to 1:10. ~Log/77!2 Particularly preferably 0.1
This can be done by coating the surface of the synthetic resin film by any method such as gravure coating, knife coating, roll coating, etc. so that the amount is 5 g/-.

When the silane compound is more than the urethane oligomer in the mixing ratio, or when the urethane oligomer is not added (Japanese Patent Application No. 1983-
97459) has excellent masking properties in a high temperature range, while on the other hand, when the amount of the silane compound is less than that of the urethane oligomer, it has excellent masking properties in a low temperature range.

However, if no silane compound is added, the adhesion to the adherend is too strong and it cannot be removed easily, or even if it is removed, contaminants remain on the adherend and the masking film has temporary adhesion. There were times when it was inappropriate to do so.

In the present invention, if the amount of the mixture of silane compound and urethane oligomer used is below the lower limit, the adhesive strength will be insufficient and the film will peel off before the start of use, or the film will peel off during deep drawing, resulting in temporary adhesion. The performance is not satisfactory for a masking film that has

On the other hand, if the amount used exceeds the upper limit, the adhesion to the adherend will be too strong and it will not be easy to peel off, making it unsuitable as a masking film with temporary adhesion properties.

The temporary adhesion masking film of the present invention enables masking at a lower temperature than the temporary adhesion masking according to the previous patent application (Japanese Patent Application No. 51-97459), and the temperature range is from room temperature to the resin melting temperature. However, the adhesion strength to the adherend is adequate even in the range of 50°C to 100°C.

Moreover, there is virtually no change in adhesive strength due to temperature, humidity, light, etc., and even when deep drawing is performed, there is no problem such as lifting of the film, and there is no contamination of the adherend after the film is peeled off.

Further, in the masking operation, the masking film is usually unwound continuously and then temporarily attached to the adherend, so the roll of the masking film must be able to be easily unwound.

Conventional masking films have a strong adhesion between the temporary adhesion layer and the back side of the base synthetic resin film, making it difficult to unwind them as they are, so the back side of the film needs to be treated to make unwinding easier. The masking film of the invention does not have adhesiveness between the films and can be easily rewound, and does not require special backside treatment.

The present invention will be explained below using examples.

As an example masking film, the temporary adhesive masking film of the present invention (Film-A) is shown below.

B) Previously filed a patent application (Japanese Patent Application No. 51-59459) L.

A temporary adhesion masking film (Film-C) was prepared and compared with two conventional products (Films D and E) in terms of adhesive strength and lifting properties after deep drawing.

(1) Production of films A and B (masking films of the present invention) A polyvinyl chloride resin is used as the base material of the film, and after adding a plasticizer (dioctyl phthalate) stabilizer to this, the thickness is reduced to 0 by a conventional calendering method. A .07 mm film was obtained, and a mixture of a silane compound and a urethane oligomer having a mixing ratio of A) 1:5 and B) 1:0.5 was coated on one side of the film to obtain Film A and Film B.

That is, mono-β-aminoethyl-γ-aminopropyltrimethoxysilane was used as the silane compound, and polyester diol (polyneopesity adipate), neopentyl glycol, and tolylene diisocyanate were used as the urethane oligomers in a molar ratio of 1.0:2.5: 4.0 was prepared into a mixed solution of equal volumes of acetone and ethyl acetate, and used as a coating solution.

This coating solution was coated on one side of the polyvinyl chloride film by a gravure coating method for 30 minutes at a temperature of 120°C.
After drying for 0 seconds, a film having a film of a mixture of a silane compound and a urethane oligomer having a thickness of 1.0 μm was obtained.

There was no change in the transparency of this film or in the film rewindability.

(2) Production of Film C (Temporarily Adhesive Masking Film of Japanese Patent Application No. 51-96459) Using the same polyvinyl chloride as in Films A and B, film C was obtained by applying only a silane compound to one side of the polyvinyl chloride in the same manner. Ta.

That is, a solution of N-β-aminoethyl-aminopropyltrimethoxysilane as a silane compound was prepared in 10% acetone, and this coating solution was applied to one side of the polyvinyl chloride film by gravure coating for 30 seconds at a temperature of 120°C. Film C was obtained by drying.

(3) Conventional film-D1 Film-E Comparative examples include Film-D, which is made of polyvinyl chloride coated with an adhesive material whose main component is acrylic rubber, and Film-D, which is made of polyvinyl chloride coated with an adhesive material whose main component is natural rubber. Film-E was used.

A stainless steel plate (SUS 304 BA finish) was used as the adherend, and Film-A was heated at 60°C and Film-B was heated at 1
Film-D and Film-E were temporarily attached to adherends at room temperature.

10 for the adhesive strength between the masking film and the adherend.
The effects of heating under heating and the effects of heating and humidification after 0 and 200 hours of processing were examined, and regarding deep drawing workability, the state of lifting from immediately after processing to 7 days after processing was examined.

As shown by comparison in Table 1, the temporary adhesion masking film of the present invention was equivalent to the conventional masking film in terms of initial adhesive strength, but the adhesive strength of the conventional masking film increased due to the action of ultraviolet rays and heat. In contrast, the temporary adhesion masking film and Film-C of the present invention do not increase their adhesive strength and can be easily removed even in practical use. It was a film that could be peeled off, had no staining properties, and had excellent temporary adhesion properties.

Furthermore, while the adhesive strength of the conventional masking film was significantly reduced due to the effect of humidity, there was no change in the adhesive strength of the masking film of the present invention and Film-0.

Regarding deep drawing performance in the field of deep drawing applications, after deep drawing the stainless steel plate to which a masking film was temporarily attached using a deep drawing test machine manufactured by German company Eleksen, we observed the lifting state of the film over time and evaluated it. did.

As shown by comparison in Table 2, the masking film of the present invention and Film-C exhibited good deep drawability with no floating even after deep drawing.

However, it has been shown that conventional masking films have very poor deep drawing suitability and cannot be used as metal protective films.

That is, as a reference example, the current 5olvent Coa-
Table 2 also shows the results of a comparative evaluation of the lifting of the film after deep drawing in the surface protective film by the ting (S, C) method using the masking film of the present invention.
However, it was shown that the masking film of the present invention can be used in the case of a surface protective film by the current S and C methods and under the same usage conditions as Film-0.

Claims (1)

[Claims] 1 At least one substituent selected from the group consisting of methoxy group, ethoxy group, silanol group, chloro group, acetoxy group, β-methoxy group, t-butylperoxy group, and vinyl group, octoxy group, glycyl group, mercapto A mixture of a urethane oligomer and a silane compound having at least one substituent selected from the group consisting of a group consisting of an epoxy group, an epoxy group, and an amino group is applied to the surface of a synthetic resin film to form a film to form a temporary adhesion layer. Features: Temporary adhesive masking film for metals.