JPS5824270B2 - Bousei polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention effectively prevents rusting by coating conductors made of copper or copper-based alloys in electric wires and cables, and also reduces the required amount as a constituent material of electric wires and cables.
This relates to a surface-coated rust-proof polyester film with excellent properties.

One of the applications of polyester film is for wrapping and covering conductors in electric wires and cables.

That is, a conductor made of copper or a copper-based alloy is wrapped and covered with a polyester film, and then a predetermined insulating coating is made of crosslinked polyethylene or the like.

The main functions of polyester film here are its good electrical insulation properties, electrical insulation properties due to its heat resistance,
Due to its good mechanical strength and heat resistance, it functions as a binding tape for multiple conductors, or as an identification tape for each conductor in a multi-core cable when colored polyester film is used.

Here, it is very important to protect conductors in electric wires and cables from corrosion, and for this reason, polyester films that have a rust-preventing function for copper and copper-based alloys are being used.

This is done by using a rust-preventing polyester film coated with a resin containing a volatile rust preventive agent on the side that comes into contact with the conductor, and the rust preventive agent gradually transfers to the conductor surface through contact or vaporization, corroding the conductor. It protects from

However, conventional anticorrosive polyester films are not sufficient in the following points.

(1) The adhesion of the coating resin to the polyester film is insufficient, resulting in wear and tear from the contacting rolls and impact during slitting during the process of slitting wide film into narrow tape, tape (film) rewinding process, etc. When the coated resin is detached (especially at the edges of the tape), this detached coated resin powder also transfers to the non-coated surface of the tape (film), and when the conductor is continuously coated with cross-linked polyethylene. ,
This detached resin accumulates as slag at the inlet of the mandrel, impeding continuous work.

This accumulation of slag is thought to be prevented by improving the adhesion of the coating resin to the polyester film, increasing the softening point, improving abrasion resistance, optimizing the degree of surface roughness, and optimizing the thickness of the coating layer. .

In other words, improving the adhesion of the coat resin to the polyester film, improving abrasion resistance, and optimizing the degree of surface roughness are intended to prevent the coat resin from detaching, and improving the softening point of the coat resin is to Optimizing the thickness of the coating resin is effective in preventing the accumulation of fusion at the core part and blocking of the coating film (transfer between films), and in obtaining smooth conductor passage characteristics at the core metal part. it is conceivable that.

(2) When a finished electric wire or cable is disassembled, the polyester film coat membrane is transferred to the conductor and detached from the film layer, which is unfavorable in terms of the characteristics of the electric wire or cable or the characteristics of disassembly.

This is 170~
This is because it takes about 3 to 5 minutes at a temperature of about 190° C. and a pressure of about 20 to 30 ky/ffl.

Prevention of this migration is a matter desired by electric wire and cable manufacturers.

The present invention aims to solve these problems and provide a surface-coated anticorrosion polyester film having excellent anticorrosion properties.

The identification tape function is a function that has been attracting attention in recent years, and for this reason, the use of white polyester films blended with titanium oxide etc. as base polyester films is prominent. Because the adhesion of the coated resin is poorer than that of ordinary clear polyester film,
The coating resin used here is required to have even stronger adhesion properties.

Because heat resistance is required in the field of electric wires and cables,
The coating resin is preferably a thermosetting heat-resistant resin.

Benzotriazole is an excellent rust preventive agent for copper and copper-based alloys (Japanese Patent Publication No. 39-6069), and a suitable coating composition is one in which benzotriazole is added to the thermosetting heat-resistant resin.

However, as a result of a copper plate coating test of a polyester film coated with a composition containing benzotriazole added to an epoxy resin, a thermosetting polyester resin, etc., it was found that the anti-rust properties are not always sufficiently exhibited. found.

From this, it is considered that it is necessary to select the coating resin from the viewpoint of antirust effect, and also to optimize the amount of benzotriazole added.

It goes without saying that this coating resin must be selected to have excellent adhesion to the polyester film.

Furthermore, it is desirable that the coating resin has good abrasion resistance.

Furthermore, it is considered desirable that the surface of the benzotriazole-containing coating film be smooth (with a low degree of surface roughness) from the viewpoint of wear resistance.

On the other hand, it is necessary that the coating composition has good coating properties.

Further, it is suitable that the coating film can be dried and cured under the usual conditions for continuous polyester film coating, such as a coating resin drying and curing temperature of 150 to 180°C and a drying and curing time of 30 to 60 seconds.

The present invention was achieved as a result of various studies in consideration of the above points, and its gist is that it mainly contains a silicone acrylic resin, an incyanate resin (B), and a benzotriazole (C). component, whose solid content weight ratio is (B)/(A) = 10 to 70/100, (C)
/(8)+(B)=0.1 to 40/100 A rust-proofing polyester film for protecting copper and copper-based alloys is provided.

One of the features of the present invention is that a mixed composition of a silicone acrylic resin and an incyanate resin is used as the coating resin.

The mixed composition of the present invention causes the necessary curing reaction under normal continuous coating conditions for polyester films, forms a coating film with excellent adhesion to polyester films, heat resistance, abrasion resistance, and surface smoothness, and This composition to which benzotriazole is added in the above amount exhibits an excellent antirust effect when copper or a copper-based alloy is coated with this coated polyester film.

This is because benzotriazole is well distributed in the surface layer in the cured silicone acrylic-isocyanate resin coating, and what is in the coating film moderately blooms to the surface layer and even volatilizes, resulting in copper and copper-based alloys. It is understood that it exhibits a rust-preventing effect against.

One of the effects of using isocyanate resin in the present invention is to improve the hardness of silicone acrylic resin, which has relatively good coating film hardness among silicone resins, to a usable hardness, and to improve abrasion resistance. The purpose of this invention is to perfect the curability of the silicone acrylic resin, which cannot be sufficiently cured under normal polyester film coating conditions using a single silicone acrylic resin.

A silicone acrylic resin coated film with a thickness of about 3 μm is cured at 150 to 180°C, several tens of degrees.
Heat treatment for more than a minute is required, but when an appropriate amount of isocyanate resin is added to this, the temperature is 150-180℃.
The process takes place in 30 to 60 seconds and is extremely effective in preventing deterioration of the polyester film and improving coating efficiency.

Here, the silicone acrylic resin is a modified silicone resin that is generally referred to as a silicone wanist.

That is, silicone varnish is mainly composed of methyl silicone varnish and phenyl silicone varnish, and methyl silicone varnish is generally 5102.

CH3S 103 / 2 + (CH3) SiO
t (CH3)3S 1012 structure, phenyl silicone varnish is C6H55IO3/2, C6H3
It consists of the structural unit CH3SiO9(C6H3)2S10.

Silicone acrylic resins are made by chemically (cocondensation) or mechanically (blending) modifying these silicone varnishes with acrylic resins. More desirable.

Examples of this silicone acrylic resin varnish include Shin-Etsu Chemical Co., Ltd. (Shin-Etsu Silicone KR-5208, KR
,-5203, Mitsubishi Rayon Duraclone 5E-1
390 etc. are mentioned.

In this silicone acrylic resin varnish, the higher the silicone component ratio, the better the heat resistance of the cured film, but the resin curing becomes slower, and the higher the acrylic component, the lower the heat resistance of the cured film, but the cure The process becomes faster and the coating film hardness also becomes higher.

Commercially available silicone acrylic resin varnishes have appropriate ratios of these components and can be effectively utilized.

Further, the isocyanate resin is a resin having a highly reactive incyanate group at the end, and this incyanate group causes an isocyanate reaction with various functional groups, such as a -0H group, and causes a rapid curing reaction.

These incyanate resins mainly include 2,4-tolylene diisocyanate, 2,6-49 diisocyanate, diphenylmethane-4,4'-diisocyanate, a reaction product of trimethylpropanol and tolylene diisocyanate, and phenylene diisocyanate. and various modified forms thereof, examples of which are as follows.

Shin-Etsu Silicone KR-302B manufactured by Shin-Etsu Chemical Company, Takenate A-3 manufactured by Takeda Pharmaceutical Company Limited, Takenate A-10 manufactured by Takeda Pharmaceutical Company Limited
, Coronate L manufactured by Nippon Polyurethane Industry ■, Millionate T-80 manufactured by Hodogaya Chemical Industry ■, Millionate T-1 manufactured by Hodogaya Chemical Industry ■
00, Desmodule M manufactured by Bayer, Sanyo Chemical Industries ■
Seisaku Tsunofretsu E etc.

The blending amount of the silicone acrylic resin and the incyanate resin must be within the range of 10 to 70 parts by weight of the incyanate resin solid content per 100 parts by weight of the silicone acrylic resin solid content. If the amount of resin blended is less than this, the integral curing reaction will be insufficient, and the curing process of the coated film will be insufficient and difficult.

Furthermore, the coating film has insufficient hardness and lacks abrasion resistance.

If the amount of isocyanate resin is more than this, the pot life of the coating solution becomes too short and gelation of the solution occurs during the coating process, and the film also becomes too hard and brittle, and the adhesion of the coat film is reduced.

In addition, when it is desired to further speed up the curing of the coat film at a low temperature while maintaining the coat film properties such as coat film adhesion, appropriate coat film hardness, and good coat surface flatness, various organometallic salt catalysts such as Metal salts of organic acids such as octylic acid or naphthenic acid, i.e. lead, iron, Kobal 1, zinc,
Addition of tin salt, etc., ethyl titanate, butyl titanate,
Addition of triethanolamine, choline hequinate, etc. is effective.

It goes without saying that the amount of these additives needs to be optimized considering the pot life.

The amount of benzotriazole added as a rust preventive agent for copper and copper-based alloys is 0.1 parts by weight per 100 parts by weight of the total solid content of silicone acrylic resin and isocyanate resin.
-40 parts by weight is required.

If the amount of benzotriazole added is less than this, the rust prevention effect will hardly be exhibited, and if the amount of benzotriazole added is more than this, the coating film density, coating surface flatness, or coating film heat resistance (benzotriazole Melting point 90-9
5°C), etc.

By coating a polyester film with an organic solvent solution of a mixed composition of silicone acrylic resin, incyanate resin, and penzotriazur in an appropriate range as described above, and adhering the cured coat film to the surface of the polyester film. A rust-proof polyester film is obtained.

The coating film thickness is empirically determined to be 0.5 to 5 μm, particularly 1.0 to 3 μm.
A range of 0μ is appropriate, and the degree of surface roughness of the coat film is also preferably 3μ or less.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to these Examples unless it exceeds the gist thereof.

In the following examples, parts expressed as percentages are by weight.

Example 1 25μ thick white (titanium oxide blend) polyester film [Mitsubishi resin Diafoil White #25],
After drying and curing, the following compounded composition was applied to a coating thickness of about 3μ on one side to obtain a white rust-proof polyester film with a thickness of about 28μ (coating conditions: drying and curing temperature 150°C,
dry curing time 30 seconds).

Note: 1) Manufactured by Shin-Etsu Chemical silicone acrylic resin 2) Isocyanate resin 3) Organometallic salt The test results are shown in Table 1.

Example 2 In the same manner as in Example 1, an approximately 28μ thick white anti-rust polyester film CB) was obtained from the following blended composition.

The test results are shown in Table 1.

Example 3 In the same manner as in Example 1, the following compounded composition was applied to a 25μ thick clear polyester film (Diafoil #25 manufactured by Mitsubishi Plastics ■) to obtain an approximately 28μ thick clear antirust polyester film (c).

Note: 4) Made by Mitsubishi Rayon ■ silicone acrylic resin 5) Sanyo Chemical Industry Can Isocyanate resin The test results are shown in Table 1.

Example 4 Thyroid #244 (
5 parts of amorphous silica particles (manufactured by Fuji Davison) were added,
In the same manner as in Example 1, a white anticorrosive polyester film Δ having a thickness of about 28 μm was obtained.

The test results are shown in Table 1.

Comparative Example 1 In the same manner as in Example 1, a white anticorrosive polyester film (about 28 μm thick) was obtained from the following blended composition.

Note 2 6) Comparative example of thermosetting polyester resin made by Union Varnish ■ 2 In the same manner as in Example 1, approximately 28μ
Thick white anti-corrosion polyester film (sold separately).

Note) Table 1 shows the epoxy resin and varnish test results made by Union Varnish ■.

Table 1 shows the results of comparing the properties of Examples 1 to 3, Comparative Examples 1 to 2, and the commercially available white anticorrosive polyester films manufactured by Ni Co., Ltd. (base film was Diafoil #25■White) F and G.

(Note 1) Strongly stick Nichiban 24-width cellophane tape onto the coated surface of the sample film using your fingers (pressure load: approx. 2 kg).
, the detachment of the coating film from the sample film was observed when the cellophane tape was rapidly peeled off.

Judgment 20 (no to slight detachment) △ (partial detachment) × (significant detachment) (Note 2) Rub the sample film strongly with both hands 20 times and spread it to see if the coating film peels or detaches. .

Judgment is based on (Note 1).

(Note 3) A sample film was wrapped around 7 concentric copper wires with a wire core diameter of about 1 mm, side-wound and overlapping so that the coated side was on the copper wire side.
Heat pressing was performed at 0 ky/ffl for 5 minutes, the sample was rapidly cooled with water, and the sample film was peeled off from the copper wire, and the detachment (adhesion to the copper wire) of the coating film was observed.

Judgment is based on (Note 1).

(Note 4) A test will be conducted on an actual machine at a wire and cable manufacturer, and the coating layer will be dismantled and the sample film will be peeled off from the copper wire to see if it detaches (transfers to the copper wire).

Judgment is based on (Note 1).

(Note 5) Tested using our tape abrasion testing machine.

The test outline is to run a sample film 127ILrIL width slit tape at a speed of 19,771/min, press the slit tape with a plated metal body and a cushion body with a load of 250g, and after running 200 m, fine particles attached to the plated metal body are Collect the powder and measure its precipitation.

In this case, the non-coated surface is brought into contact with the plated metal body.

The sample tape used was a coated film with a width of 500 mm that was re-wound once and then slit into a width of 12 mm.

Judgment 20 (slag deposited weight less than 2 m9) △ (slag deposited weight 2
η or more, less than 3) x (Slag precipitation weight 3η or more) (Note 6) Conduct an actual machine test at the wire manufacturer and check the slag accumulation state at the core metal part.

Rating: 20 (almost no discoloration) △ (slight browning) Two test films are heated and pressed, and when the two sample films are peeled off after pressing, the pressing temperature at which adhesion and peeling of the coated surface occurs is determined.

(Note 9) Measured using Talysurf surface roughness meter manufactured by Taylor Hobson.

As seen in Table 1, the anticorrosive polyester film according to the present invention is extremely suitable for winding wires and cables.

Claims (1)

[Claims] 1 Silicone acrylic resin (A), isocyanate resin (B) and benzotriazole (0 is the main component, the solid content weight ratio is (B) / (A) = 10 to 7
0/100, (C)/cA)+(Bl-0,1~40
/100 A rust-preventing polyester film for protecting copper and copper-based alloys, characterized by having a NALCOAT film.