JPS6071254A - Easy adhesive polyester 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 The present invention relates to an easily adhesive polynisdel film useful as a base film for magnetic tapes such as video tapes.

Information media has made remarkable progress in recent years, especially videotapes,
Many proposals have been made regarding magnetic media based on polyester films, such as computer tapes and floppy disks. Among these, magnetic tapes made by applying magnetic paint to a polyester base are the most common and are used in a variety of fields.

The base polyester film to which the magnetic paint is applied needs to have appropriate adhesion to the magnetic paint. If this adhesive force is small, the tape will have significant one-to-one mating, and the magnetic coating may peel off under severe practical conditions for the tape. In particular, it is essential to improve the adhesive strength in order to improve the durability against stress when stopping and starting the i31 on a magnetic tape, the tapping durability on a floppy disk, and the like.

Of course, improving the adhesive strength of the base film and magnetic paint can be done by improving the magnetic paint itself, but since the polyester of the base film is highly crystalline and has low adhesive strength, the adhesive strength of the base polyester film can be improved. That is of great significance.

Various methods have been proposed in the past as means for facilitating adhesion of base films. There are methods such as adding and blending an adhesion-facilitating substance to the polyester for the base film, and applying an adhesion-facilitating primer solution to one or both sides of the film.

In addition to the above-mentioned improvement in adhesive strength, in industrial production, it is also important to collect and reuse waste film in the film forming process from the viewpoint of improving the product yield of the film. However, in the conventional method, substances mixed into the polymer (or film primer substances) may decompose during recovery, re-melting, or aggregate to form foreign matter, making it difficult to regenerate a uniform film. It became. On the other hand, in terms of productivity, the additive blend type has disadvantages such as differentiation from other chips, and the primer type has problems such as solvent treatment. Furthermore, as a type of primer, a method is known in which the coating is applied within the production line at the time of production, but in this method, the medium is limited to water-based, making it difficult to select a substance that can easily adhere, and if a solvent is used. There is a problem in that the equipment becomes extremely expanded and complicated.

It is an object of the present invention to solve these problems and provide a polyester film that has extremely high adhesive strength, excellent waste recovery properties, and high productivity.

The present inventors have discovered that the above object can be achieved by hot-melt coating a polyester film with a polyester resin mixture having a specific melt viscosity and molecular weight, and have arrived at the present invention.

That is, the present invention has a melt viscosity of 100 at 160°C.
Polyester resin (A) with poise or higher 2 to 99
Weight% and melt viscosity at 160℃ is 100 pois
A mixture ('C) consisting of 98 to 1% by weight of a polyester resin (B) having an average molecular weight of less than e and an average molecular weight of 10,000 or less
on at least one side of the high molecular weight polyester film,
It is an easily adhesive polyester film obtained by hot melt coating.

In this bot melt coating, the mixture (C) is applied to at least one side of a running high molecular weight polyester film having an intrinsic viscosity of 0.4 or more before the crystal orientation is completed, in a molten state by a die coating method. So 5
It is preferable to apply the film to a thickness of 0 μm or less, then stretch the film in at least one direction, and heat treat it to complete the crystal orientation.

The polyester film of the present invention has the following characteristics.

a)! i Extremely high adhesion to magnetic paint.

b) High adhesive strength to the metal vapor deposited layer.

C) There is a great possibility of collecting and reusing the film.

d) It is economical because it can be manufactured in-line.

The polyester resin (A> in J3 of the present invention is 160°C
The melt viscosity at is 100 pOise or more. When the melt viscosity is less than 100 poiSe, there is no need to blend the low-viscosity polyester resin (B), but the coating film is likely to cause blocking.

Further, the polyester resin (B) has a melt viscosity at 160°C of less than 100 poise and an average molecular weight of 1
0000 or less. This melt viscosity is 100 pOi S
If it is more than e, the uniformity of the coating film is poor and the coating properties are also poor. Moreover, when the average molecular weight exceeds 1oooo, the uniformity of the coating film is poor and the coating properties are also poor.

Polyester resins (A) and (B) are produced from arbitrary raw materials by conventional methods. As the dicarboxylic acid component of the polyester resin, prephthalic acid, isophthalic acid, 4,4
Examples include aromatic dicarboxylic acids such as diphenyldicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and phthalic acid, and aliphatic carboxylic acids such as adipic acid, sebacic acid, and dodecanedicarboxylic acid. In addition, glycol components include ethylene glycol, propylene glycol,
1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-bentanediol, 1,6-hex4onediol, 1,4-cyclo-xane dimetatool, ρ-xylylene diome , bis°noenol to ethylene oxide (=J addition), etc.Furthermore, ε-prolactone, 1)-hydroxybenzoic acid 1, bisphenol A, hydroquinone, etc. can also be used.

The polyester resin (Δ) and (B) may be added with a lubricant (inorganic particles, organic matter) during or after polymerization, if necessary.
, fronking inhibitor, mold release agent, adhesion aid, heat stabilizer,
Colorants etc. can be mixed.

In the present invention, a mixture (C) is prepared by mixing 2-99% by weight of polyester resin (A) and 98-1% by weight of polynisder resin (B). polyester resin (A),
Mixing (B) can be carried out by putting the pellets, flakes, etc. of the mixture obtained by kneading with an extruder, kneader, etc. before coating into a hot melt raw material supply tank and feeding it to a die after mixing, or by using an arbitrary method. Select a method.

The high molecular weight polyester film in the present invention preferably consists of high molecular weight polyester having an intrinsic viscosity of 0.4 or more. Such polyesters are high-melting point, high-crystalline, linear saturated polyesters synthesized from aromatic dihydrochloric M acids and diols, and include polyethylene terephthalate-1, polyethylene isophthalate, polybutylene terephthalate,
Examples include polyethylene-2,6-naphthalate, polyarylate, copolymers thereof, and blends thereof with other resins. If necessary, a suitable amount of a lubricant, a colorant, a heat stabilizer, an ultraviolet absorber, etc. can be added to the high molecular weight polyester.

The polyester resin mixture (C) is applied to at least the bottom surface of the high-molecular-weight polynysdelphile using the Kotmel method.

The method of small melt coating can be selected arbitrarily.

Among these, polyester resin mixture (C) is applied to an unstretched sheet made by extruding high molecular weight polyester from a die and applying static electricity on a cooled drum, or to a film made by stretching the same in the longitudinal or transverse direction. It is preferable to melt and discharge from a tie and apply by a hot melt coating method. In this case, it is possible to coat not only one side of the film but also both sides. When applying to both sides, it is possible to arbitrarily select whether to apply at the same time (same position) or to apply to one side and then to the other side. The distance between the die lip surface and the running film surface can be arbitrarily selected. When coating, pressure can also be applied to the film and the melt resin.

The average thickness of the mixed polyester resin layer after coating 5 is 50μ
Adjust as below. If it exceeds 50μ, it is difficult to form a uniform film. In particular, it is preferable that the thickness is 5 μm or less.

After coating the polyester resin mixture (C), it is stretched in at least one direction at an arbitrary point (position), and finally the crystal orientation of the base film is completed by heat treatment. In this way, an easily adhesive film coated with a primer on one or both sides is formed.

Since the easily adhesive polyester film of the present invention has high adhesive strength, it is extremely useful as a base film for magnetic tape coated with magnetic paint.

The following examples are given to explain the embodiments of the present invention in more detail, but the examples given here are only a few examples and the invention is not limited thereto.

In addition, the adhesive strength in the examples was measured by the following method.
.

〔Adhesiveness〕

Primer-coated polyester film was coated with magnetic coating O'4 under specified conditions, and Scotch tape No. 6 was applied.
00 (3M “IJ”) rl 19.4mtn
A 8 cm long piece is glued without air bubbles, and the top is smoothed with a manual front roll according to JIS, C2701 (1975), and a 5 cm long adhesive layer is covered with Tensilon UM-II manufactured by Toyo Baldwin Co., Ltd. Peel off one character of this material at a head speed of 300#/min using a
Measure it as cm. In addition, in single-character peeling, the laminate was taken with the tape side facing down, and the distance between the telephotos was 5 cm.

[Preparation of paint for evaluation]

(1) Nido O Cell O-Z R31/2 as lacquer thinner for Vt1i1 paint
(manufactured by Flakes Daicel @ containing 25% isopropanol) to prepare a 40wt% solution, and the solution was
part, followed by polyester resin (Desmofene #1700
Bayer) 325 parts, chromium dioxide magnetic powder 260
47r, soybean oil fatty acid (Region P; manufactured by Riken Vitamin ■), cationic activator (Cation A8 manufactured by NOF ■), and squalene (Shark 111 oil) as a dispersant/wetting agent.
1 part, 0.5 part and 0.8 part of each were put into a ball mill. Methyl ethyl ketone (hereinafter abbreviated as M E K)
282 parts of a mixed solution consisting of /cyclohexanone/toluene = 3/4/3 (weight ratio) is further mixed and sufficiently softened to prepare a mother liquor paint (45 wt%). To 50 parts of this mother liquor, 43 parts of an addition reaction product of trimedylolpropane and tolulein diisocyanate (Coronate, manufactured by Nippon Polyurethane Industries) was mixed with 6.25 parts of butyl acetate.
% and finally 42.75 wt% Evaluation Examples 1 to 6 and Comparative Examples 1 to 2 Polyethylene terephthalate with an intrinsic viscosity of 0.65 containing a small amount of inorganic fine particles was extruded to make an unstretched sheet. Then, the sheet was stretched 3.6 times in the longitudinal direction while heating. This traveling uniaxially stretched film (thickness 40μ
), various terephthalic acid/isophthalic acid/adipine II/ethylene glycol/neopentyl glycol/diethylene glycol copolyester (polyester resin A) and various terephthalic acid/isonotal 1
! I/ethylene glycol/neopentyl gallicol copolymerized polyester (polyester resin B) with a pre-mixed pre-mixed chip (Table 1 shows the resin properties and mixing ratio. Each composition was added in small amounts to prevent blocking. (containing a lubricant) was discharged from the die and die-coated only on one side to form a film with a thickness of 4 μm. Thereafter, this coated film was stretched 3.9 times in the transverse direction while heating.
A primer-coated film having a thickness of 11 μm was obtained by heat treatment at 00° C. for 7 seconds. The properties of this film are shown in Table 1.

In Examples 1 to 6, a single layer of uniform primer was formed and the adhesion to the magnetic paint was high, but on the other hand, in Comparative Examples 1 to
In No. 2, the melt viscosity was too high, so the thickness unevenness of the primer layer was large and defective (see the margins below).

Claims (1)

[Claims] 1.The melt viscosity at 160°C is 100 points/s (p
oise) or higher (A) 2 to 99
The weight percent and melt viscosity at 160°C are 100 voices (p
. A mixture (C) consisting of 98 to 1% by weight of a polyester resin (B) having an average molecular weight of less than Easy adhesive polyester film. 2. The mixture (C) described in item 1 above is melted by die coating on at least one side of a running polymer omega polyester film having an intrinsic viscosity of 0.4 or more before the crystal orientation is completed. The easily adhesive polyester film according to claim 1, which is obtained by coating the film to a thickness of 50 μm or less, then stretching the film in at least one direction, and heat-treating the film to complete crystal orientation.