JPS6021673B2 - thermal adhesive polyester film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-adhesive polyester film used for electric wire wrapping tapes, protective covering films, etc.
In particular, it relates to a coated polyester film that has improved slip properties, transparency when laminated, anti-blocking properties, etc. without impairing adhesive properties.

Polyester film has excellent mechanical, electrical, and thermal properties, so it is used as a wrapping tape for covering and reinforcing electric wires, and is also used for protection and covering films for metals and plastics. has been done.

Of course, since the polyester film itself is highly crystalline and has a high melting point, it cannot be thermally bonded like polyethylene, and an adhesive must be used to impart thermal bonding properties. Polyester adhesives with similar compositions are suitable as adhesives for polyester films, but those with good adhesion generally have blocking properties, and those with no blocking properties have poor adhesion. be.

Therefore, in order to eliminate this drawback, studies have been made to incorporate PVC-acetic acid picopolymer resin, anti-blocking agents (inorganic fillers, styrene-hydro-maleic acid copolymers, etc.).

However, it could not be used for wrapping tapes because the balance between adhesiveness and blocking resistance was poor. An object of the present invention is to obtain a heat-adhesive polyester film that has improved flocking resistance and slipperiness without substantially impairing adhesiveness.

As a result of intensive research for this purpose, the inventors
By combining various copolyesters with finely divided silicic anhydride, it was possible to improve the above-mentioned drawbacks and obtain a heat-adhesive polyester film which can be used as a wire wrapping tape or a protective covering film.

In the present invention, the film serving as the base is 85 mol%
The above is a polyester film composed of a dibasic acid residue of terephthalic acid and a glycol residue, and a biaxially stretched film of polyethylene terephthalate is mainly used.

The copolyester used as the first component of the coating agent in the present invention has terephthalic acid residues as the dibasic acid component and ethylene glycol residues as the glycol component.
0-50 mol%, triethylene glycol residues 75-4
0 mol% and the glycol residue shown in the following general formula is 20
~5 mol%.

It has a general formula of an integer composition of m and n=1 to 3, and is a relatively European resin with a glass transition point (Tg) of 100 to 3000 and a softening point (ring and ball type) of 120 to 150 o.

The intrinsic viscosity is phenol/tetrachloroethane = 6/4 (
It is preferable that the value measured at 30 qo after dissolving in a mixed solution of (weight ratio) is 0.7 to 1.0. The copolyester used as the second component of the coating agent has a composition consisting of terephthalic acid residue as the dibasic acid component, 20 to 50 mol% of ethylene glycol residue as the glycol component, and 80 to 50 mol% of neobentyl glycol residue. The glass transition point (Tg) is 60o ~ 80qo, the softening point (
Ring and ball type) It is a relatively hard resin with a temperature of 160°C to 200°C. Intrinsic viscosity (measurement method is the same as the first component) is 0.5 to 0
．． 8 is preferred. Further, the fine particle anhydrous silicon added as the third component of the coating agent has a Si02 content of 99.
It is preferable to have a primary particle size of 8% or more and a primary particle size of about 7 to 15 m.

As a specific example, AEROS Yama 200 and 30G manufactured by Nippon Aerosil Co., Ltd. can be used. The coating agent in the present invention is a mixture of 65 to 85 parts by weight of the first component, 10 to 25 parts by weight of the second component, and 5 to 5 parts by weight of the third component, dissolved in the above-mentioned three-component solvent or A coating solution is produced by decomposition, but in order to obtain a coated film with good performance, it is necessary to moderate the dispersion of the fine particles of silicic anhydride.

That is, the primary particle diameter of the fine silicic anhydride used in the present invention is approximately 7 to 18 h, but in reality, many particles are assembled to form relatively large particles, and when these are decomposed in a solvent, Normally, it is not possible to separate the primary particles, and many molecules come together to form a three-dimensional silk-like structure. The diameter of the associated particles largely determines the performance of the coated film. In other words, if it is too large, the coated surface will become cloudy and rough, which is suitable for preventing blocking, but the adhesion will be completely poor.
On the other hand, if it is too small, the coated surface will be transparent and smooth, resulting in good adhesion but poor blocking properties. The aggregate particle size necessary to satisfy both of these performances is about 1 to 5 mm. As described above, fine particles of silicic anhydride are associated with each other, so a coating solution containing the silicic acid has no precipitation of silicic anhydride, and has good coating permeability due to its thixotropic property. Copolyester, which is a component of the coating liquid used in the present invention, is a mixture of a first component that is a relatively soft resin and a second component that is a relatively hard resin.

The first component is effective in adhesion to the base polyester film and thermal adhesion to the laminated adherend, and the second component does not impair adhesion and is useful for reducing blocking properties. In addition, the blocking property could be further reduced by incorporating fine particle silicic anhydride. The above copolyesters are soluble in organic solvents.

Good solvents include halides such as chloroform and methylene chloride, and ethers such as dioxane and tetrahydrofuran, but mixed solvents such as toluene and acetone and toluene and methyl ethyl ketone are practically preferred. In the present invention, a copolyester in which fine particles of silicic anhydride as described above are dispersed is applied to one or both sides at a ratio of 5 to 3 parts per solid content.

Such a coating thickness is necessary to obtain good adhesive strength. The present invention will be specifically described below with reference to Examples.

Note that the measurement items in the examples were measured by the following methods. '1}
Adhesive Strength The coated surface of the sample was combined with a polyethylene terephthalate film (thickness: 16 mm) and laminated using a test laminator.

Lamination conditions: Temperature 150qox Pressure 2k9/Ground x Speed 0.8 skin/min Cut out 25 skin test pieces from the laminate product and test the T-peel strength using a Shimadzu Autograph at a peeling speed of 2 specific ribs/min. was measured.

(Based on ASTM187) '2} Cut the blocking resistance sample into 10 skin xloc pieces, match the coated side and back side (polyethylene terephthalate film side), apply a load of 5k9 to this, and leave the film at 50oo for 4 hours. Judgment was made based on the condition when peeled off.

A: Those that could be peeled off with almost no resistance B: There was some resistance when peeled off, but there was almost no adhesion of the coating resin to the peeled back surface.

C: When peeled off, the resistance is high and the coating resin adheres to the back side of the peeled surface.

Example 1 [1' The first component, the soft copolyester, is a brewing component:
Terephthalic acid residue 100 mol% Glycol component: 30 mol% ethylene glycol residue 60 mol% triethylene glycol residue 10 mol% 2,2-bis[4-(2-hydroxyethoxy)phenyl]-propane residue Glass transition point (Tg) 21℃, softening point (ring and ball type)
140oo, intrinsic viscosity [phenol/tetrachloroethane = 6 no 4 (weight ratio) measurement temperature 30 o'clock C] 0.90'2
1. The hard copolyester as the second component is brewing component: Terephthalic acid residue 100 mol% glycol component:
With a composition of 40 mol% ethylene glycol residue and 60 mol% neobentyl glycol residue, the glass transition point (Tg) is 63 qo, the softening point (ring and ball type) is 170 qo, and the intrinsic viscosity (measurement conditions are the same as European copolyester) is 0.61. I used these together.

'31, as the third component of fine particle silicic anhydride, the average density of the primary particles is approximately 12 hours.
Approximately 60 minutes/so Si02 content
Silicic anhydride (product name “A”) of 99.8% or more
EROSIL 20 and Nippon Aerosil Co., Ltd. were used.

The above third component is methyl ethyl ketone/toluene = 5/
A coating liquid having a solid content of 25% (by weight) was prepared by dissolving and dispersing it in a mixed solvent of 5% (by weight) in the proportions shown in Table 1.

In producing this coating liquid, silicic anhydride is dispersed in methyl ethyl ketone for about 30 minutes using a high-speed sieve machine to obtain a dispersed particle size of 1 to 5 µm, and this is added to a solution of polyester resin. Added and blended. This coating solution was applied onto a 16 mm thick polyethylene terephthalate film (trade name "Lumirror #16'' manufactured by Toray Industries, Inc.) using an applicator so that the coating film thickness when dry was 10 mm. It was dried to obtain a sample film.

Table 1 shows the results of measuring the adhesive strength and blocking resistance of this film using the methods described above.

When used for the first electric wire wrapping tape, protective coating film, etc., the required adhesive strength is 300 mm/25 feet or more.

Furthermore, B is the acceptable limit for evaluation of blocking resistance. From the results in the table above, it can be seen that when the amount of silicic anhydride is kept constant and the blending ratio of the first and second components of copolyester is changed, the more the first component is, the greater the adhesion force is, but the blocking is greater. As the amount of the second component increases, blocking becomes smaller, but adhesive strength decreases.

Furthermore, when the amount of copolyester as the first component is constant and the ratio of copolyester as the second component and silicic anhydride is varied, if the amount of silicic anhydride is large, blocking will be small but adhesive strength will be reduced.

In order to maintain both adhesive strength and anti-blocking performance within a good range, the blending ratio of the three components should be adjusted to Experiment Nos. 2, 3, 9 and 10.
It turns out that the value needs to be within the range specified in the claims.

Example 2 '1' As the European quality copolyester as the first component, those having the composition shown in the table below were used.

Table 2 (0) As the hard copolyester of the second component, those having the composition shown in the following table were used.

Table 3 (m) Same AER as Example 1 for fine particle silicic anhydride
OSIL200 was used.

Table 4 shows the first component, copolyester.
Results of measuring the adhesion and blocking properties of a polyethylene terephthalate coated film prepared in the same manner as in Example 1 using a coating solution containing 7 parts by weight of copolyester as the second component, 2 parts by weight of silicic anhydride, and 8 parts by weight. shows. Even when a coated film was prepared using the combination of coating liquids shown in Table 4, satisfactory results were obtained in terms of both adhesion and blocking resistance.

Claims (1)

[Claims] 1. Dibasic acid (85% or more of which is terephthalic acid)
On at least one side of a polyester film consisting of residues and glycol residues, (1) terephthalic acid residues as dibasic acid components, 20 to 50 mol% of ethylene glycol residues as glycol components, and 75 to 40 mol% of triethylene glycol residues. It consists of mol% and 20 to 5 mol% of glycol residues shown in the general formula below, and has a glass transition point (Tg) of 10
Saturated linear copolyester with a softening point (ring and ball type) of 120° to 150°C, 65 to 85 parts by weight (2) terephthalic acid residue as the dibasic acid component and 20 ethylene glycol residues as the glycol component ~50 mol% and neopentyl glycol residue 50~80 mol%, glass transition point (Tg) 60°~80°C, softening point (ring and ball type) 1
Saturated linear copolyester 10-25 from 60° to 200°C
Parts by weight (3) A heat-adhesive polyester film coated with a mixture containing 5 to 10 parts by weight of fine-particle silicic anhydride. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ where m, n: integers from 1 to 3