JPS58136417A - Preparation of polyester ultra-thin film - Google Patents

Abstract

PURPOSE:To obtain a polyester ultra-thin film, by a method wherein a resin film having elongation at break larger than that of an unoriented film mainly comprising linear aromatic polyester is laminated to said unoriented polyester film under an orienting condition and the obtained laminate is oriented to reduce the thickness of the unoriented film to 3mum or less. CONSTITUTION:To at least one surface of an unoriented film of which the main resin component substantially comprises linear aromatic polyester, a resin film having elongation at break equal to or larger than that of said unoriented film is laminated under an orienting condition and the obtained laminate is oriented at least to an uniaxial direction so as to reduce the thickness of said oriented film to 3mum or less. By this method, an ultra-thin film can be easily prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing ultra-thin polyester films. More specifically, the present invention relates to a method for producing an ultra-thin polyester film by laminating a 411 constant resin film on an unstretched polyester film and stretching the resulting laminate.

Polyester films, especially polyethylene terephthalate films, have excellent mechanical properties.

It has electrical properties and is widely used as an electrically insulating material. Among these uses, for example, for capacitive elements, the capacitance increases in inverse proportion to the film thickness, so thinner films are required. The stretching ratio could not be increased due to breakage due to temperature unevenness or the grip of the film, and there was a limit to the thickness of the film that could be manufactured.

As a result of intensive studies to develop a method for producing an ultra-thin polyester film that overcomes these problems, the present invention has been developed by laminating a resin film having a certain percentage property on an unstretched film whose main resin component is aromatic polyester. , the above object can be achieved by stretching the obtained laminated film, and furthermore, if the unstretched film contains a specific proportion of an imide compound and the imide compound is extracted and removed after stretching, an ultra-thin film can be easily produced. We have discovered that it can be manufactured, and have arrived at the present invention.

That is, the present invention provides a resin film having an elongation at break equal to or greater than that of the unstretched film under stretching conditions on at least one side of an unstretched film whose main resin component is a substantially linear aromatic polyester. This is a method for producing an ultra-thin polynisdel film, characterized in that the resulting laminate is stretched in at least one axis so that the unstretched film has a thickness of 3 μm or less after stretching.

The aromatic polyester used in the present invention has an aromatic dicarboxylic acid as a main acid component, and the aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalenedicarbone glue, diphenyl dihydrosulfonic acid, diphenylsulfone dicarboxylic acid, and diphenylsulfonic acid. , diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, methyl terephthal*, and methyl inphthalic acid. Of these, terephthalic acid in %.

Isophthalic acid is preferred. In addition, glycol components include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol,
Aliphatic glycols such as hexamethylene glycol, octamethylene glycol, decamethylene glycol, etc.
Alicyclic glycols such as 1,4-cyclohexanedimethylol, etc.; hydroxyphenyl) furopane (hisphenolum), 1.1-bis(4-hydroxyphe, nyl)cyclohexane [bisphenol Zl, ? 'su (4-hydroxyphenyl)
Examples include aromatic dihydroxy compounds such as ethers. It is also possible to use an oxycarboxylic acid component in addition to the above-mentioned dicarboxylic acid component and glycol component, and the oxycarboxylic acid is oxybenzoic acid.

Examples include oxynabutoeic acid and β-hydroxyethoxybenzoic acid.

Furthermore, the aromatic polyester used in the present invention is
In addition to the above-mentioned components, a small proportion (usually 30 mole or less) of aliphatic dicarboxylic acids such as adipic acid and cepatine, and alicyclic dicarboxylic acids such as hexahydro-terephthalic acid may be contained. In addition, polycarboxylic acids such as trimellitic acid and pyromellitic acid and/or polyols such as glycerin and pentaerythritol may be copolymerized within a range where the polyester is substantially linear (usually 1 mole or less). No problem. Among these polyesters, poly(ethylene terephthalate) #tt'7tL is particularly used.

The aromatic polyester comprising component E is produced by a method known in the art.

The aromatic polyester (A) used in the present invention is a mixed solvent of phenol/tetrachrono-1-ethane (weight ratio 60
/40) Ni + constant at 11j s s°C in 4j@
The viscosity is preferably 0.4 or more, particularly preferably KO 15 or more. Furthermore, various additives such as ultraviolet absorbers, l
! There is no problem in adding stabilizers, lubricants, etc.

Further, from the viewpoint of making the film thinner, it is preferable to blend an imide compound represented by the following formula (1) and/or formula (II), for example.

%-N and 3 hits) N--...A (Ir)
In the above formula ([), D is a divalent aromatic group that does not have a group reactive with polyester, and can be omitted. Further, - is a monovalent organic group having no group reactive with polyester, and n is 1 or 2. 2. Preferred specific examples include C6~ when U is 1, full kill of 4,
c, ~1. cycloalkyl and aryl groups, and when n is 2, C1-14 fullkylene, CI-□ cycloalkylene, C1-1. An example of this is the town of Arilen.

In the above formula (n), M is a tetravalent aromatic group that does not have a group reactive with polyester, and preferred specific examples include *, X, and the like.

etc. can be mentioned. - is a monovalent organic group that does not have a group reactive with polyester; preferred specific examples include furkyl groups of C!~1., cycloalkyl groups of Cl~, and t.

These imide compounds do not volatilize or decompose under the melting conditions of the aromatic polyester, do not react with the aromatic polyester or decompose the aromatic polyester itself, and can be uniformly melt-mixed with the aromatic polyester. Furthermore, an aromatic polyester composition was formed into a film.

After stretching, the corrugated imide compound can be easily extracted and removed by treatment with an organic solvent that dissolves the corrugated imide compound and does not attack the polyester. During this extraction process, the laminated film after stretching can be easily peeled into each layer, and the thickness of the polyester film decreases depending on the amount of imide compound extracted, so using an imide compound can yield a thinner polyester film. It has the advantage of being able to

Specific examples of imide compounds include the following compounds.

Compounds represented by the above formula (I): N-olitylphthalide 1, N-decylphthalimide F,
N-lauryl phthalimide, N-myris 1,000 phthalimide, N-cetylphthalimide, N-stearylphthalimide, N-octyl-1,8-naphthalimide, N-
Decyl-118-su7talimide, N-lauryl-1
, 8-naphthalimide, N-myristyl-1,8-naphthalimide, N-stearyl-1,8-naphthalimide, N,N'-hexamethylenebisphthalimide, N',N'-octamethylenebisphthalimide,
N,N'-decamethylene bisphthalimide.

N, N'-dodecamethylene bisphthalimide, N,
N'-hexamethylenebis-1,8-naphthalimide, N,N'-octamethylenebis(1,8-naphthalimide), N,N'-decamethylenebis(l,8-naphthalimide), N,N' -dodecamethylene bis(1)
, 8-naphthalimide) I N, N' 2,2
゜4-Trimethylhexamethylene bisphthalimide,
N,N'-2,4,4-)limethylhexamethylenebisphthalimide, N,N'-1,4-cyclohexylenebisphthalimide,! -phthalimido 3-phthalimidomethyl-3,S,5-)limethylcyclohexane,
4.4'-bisphthalimide diphenyl ether,
3.4'-bisphthalimide diphenyl ether, 4.
4'-hisphthalimido diphenyl sulfone, 3. Gi-
Bisphthalimide diphenyl sulfone, 4,4'-bisphthalimide diphenylmethane, N,N'-1,4-cyclohexylene bisphthalimide.

Compound represented by the above formula (II): N,N'-dipentylbimelitimide, N,N'
-dihexyl bip melitimide, N,N'-dioctyl biromellitide ξdo, N,N'-didecyl biromellitimide, NJM'-dihexylnaphthalene-1,4,! i,8-tetracarboxylic acid diimide.

N,N'-dioctyl-naphthalene-1,4,5,8-
Tetracarboxylic acid diimide, N,N'-didecyl-
Naphthalene-1,4,j8-tetracarboxylic acid diimide group.

The amount of the imide compound to be used is preferably 5Of-.SOO parts by weight, based on 100 parts by weight of the aromatic polyester.
More preferably 4 to 250 parts by weight, particularly preferably 5. , o to 200 parts by weight. In addition, when blending an imide compound, the intrinsic viscosity of the aromatic polyester is O
It is preferable to set it as S or more, and it is preferable to set it as 41KO, 7 or more.

Furthermore, from the viewpoint of increasing the degree of polymerization, it is also preferable (and practical) to add a chain extender that has the effect of improving the degree of polymerization of the aromatic polyester in the melt molding machine. Such chain extenders include, for example, 2,t-bis(2-oxacillin),
2.2'-bis(3,1-penzoyasazin-4-one>*) can be mentioned.

In the present invention, an unstretched film is obtained by melt-casting the above-mentioned aromatic polyester or polyester composition. The thickness of the unstretched film may be any thickness such that the film thickness after stretching is 3μ or less, usually 50μ or less, preferably 40μ or less, and IPtK preferably 30μ or less.

Next, at least one side of the unstretched film has an elongation at break equal to or greater than that of the unstretched film under the stretching conditions of the unstretched film, for example, in the case of polyethylene terephthalate, at a temperature of TO to 100°C. A resin film (hereinafter referred to as a lamination film) is laminated.

The type of film for lamination is not limited to %, and for example, polyethylene terephthalate unstretched film, polycropylene unstretched film, etc. can be used, but unstretched films in which the main resin component is aromatic polyester It is particularly preferable to use an unstretched film made of the same aromatic polyester as the film (hereinafter referred to as unstretched film 5). Any lamination method may be used for laminating the unstretched film and the lamination film, and for example, the two films may be simply overlapped to facilitate peeling, which will be described later. The thickness of the laminated film is preferably the same as or thicker than that of the unstretched film, and is preferably about ioμ or more, more preferably about 100μ or more, particularly 200μ or more. One layer of this film thickness is the laminating film Kl'
Those who are familiar with film stretching techniques will easily understand that this is determined naturally from the required stretchability under the conditions of stretchability. As the laminated film, a film in which a lamination film is laminated on the top or bottom surface of an unstretched film, or a film in which an unstretched film A is laminated on both sides of the lamination film is preferably used. By forming a laminated film in this way, it is possible to carry out stretching smoothly and reproducibly, which is difficult to do with an unstretched film alone.

In the present invention, the above-mentioned laminated film is stretched Km in at least one direction, preferably in two directions. In case of biaxial stretching, simultaneous biaxial stretching.

Any method of sequential biaxial stretching may be used. The stretching method or stretching conditions are a normal aromatic polyester stretching method,
11: The stretching conditions that have been accumulated in the past can be used as they are. In this stretching, the stretching ratio is such that the film thickness of the unstretched film is 3 μ or less, preferably 2.5
It is set to be less than μ, particularly preferably less than 2 μυ.

[When the aromatic polyester is polyethylene terephthalate, the stretching ratio is usually about 6 to 20 times in terms of area ratio.

In the present invention, after the above-mentioned stretching is performed, the stretched laminated film is peeled into each layer to form a monotonous film. The stretched laminated film can be peeled off because the layers are in close contact with each other but are not bonded together. In particular, when unstretched film AK contains an imide compound represented by formula (1) or formula (II), the imide compound is dissolved in an organic solvent that does not substantially attack the aromatic polyester. The above-mentioned peeling can be carried out simultaneously with the process of dipping the stretched laminated film to extract the imide compound. In this case, the stretched laminated film naturally peels off due to the penetration of the organic solvent without relying on a mechanical method, and therefore peeling can be carried out more easily.

Examples of the predistribution solvent, that is, an organic solvent that dissolves the imide compound and does not substantially attack the polyester (does not decompose or dissolve the polyester), include methylene chloride, polyproform, etc. hydrocarbons,
toluene.

Aromatic hydrocarbons such as xylene, acetone.

Examples include ketones such as methyl ethyl ketone and methyl isobutyl ketone, and cyclic ethers such as dioxane.

The extraction treatment time varies depending on the type of imide compound, the organic solvent used, the thickness of the stretched film, and the extraction temperature, but is usually 1 second to 15 minutes, preferably 5 seconds to 10 minutes, particularly preferably 10 seconds to 5 minutes. It's a minute. Further, the extraction temperature can be appropriately selected between room temperature and the boiling point of the S-containing medium used. The extraction treatment is preferably carried out under conditions of constant film length or limited shrinkage. By this extraction process, the imide compound contained in the stretched film is 90- or more, and even 95-
It is possible to extract more than 98 chi, especially more than 98 chi. During this extraction,
The thickness of the polyester stretched film is reduced by an amount approximately corresponding to the amount of imide compound extracted. Furthermore, since oligomers can also be extracted at the same time, polyester films with very low oligomer contents can be obtained.

The peeled polyester stretched film is preferably heat treated under constant length or limited shrinkage conditions. The heat treatment temperature is preferably (stretching temperature +10°C) or the melting point of the aromatic polyester -10°C), and the time is preferably about 1 second to 15 minutes. Polyester stretched film undergoes this heat treatment lol! It can also serve as a drying method for IK*bales, and in some cases, the bales can be heat-treated at an even higher temperature.

Further, the film for stacking pigeons used for lamination with the polyester unstretched film can also be heat-treated for 1L of stretching to form a product, if desired.

In the present invention, as described above, it is possible to easily obtain an ultra-thin polyester stretched film with a thickness of 1 μm or less, which could not be obtained conventionally by using the usual polyester film stretching technique vFJ as it is. can.

The present invention will be described in detail below with reference to Examples. In addition, in the example “
"Parts" means parts by weight, and the intrinsic viscosity is in a mixed solvent of phenol/tetrachloroethane (weight ratio 60/40).
It was determined from the value measured at a temperature of 35°C. In addition, strength elongation and Young's modulus were measured using an Instone tensile tester at a tensile speed of 1.
Measured at 0.0096/min.

Example-1 and Comparative Example-1 Polyethylene terephthalate chips with an intrinsic viscosity of 0.65 were melted and extruded from an extruder under the conditions of a polymer temperature of 280°C and an average residence time of about 8 minutes to form an unstretched film with a thickness of about 30μ. I got it.

Next, apply the same chip as above to the polymer at one temperature, and then
' Melt extrusion was carried out with a residence time of about 5 minutes to obtain an unstretched film with a thickness of about 400 μm.

The above two films were superimposed and simultaneously biaxially stretched at a temperature of 90°C to 3° and 8 times in both length and width, and then peeled to a thickness of 2.
Stretched films of 1μ and 26μ were obtained. Next, each of these films was heat-treated at 180° C. for 2 minutes at a constant length. The obtained film had a strength of 27.8 kg/-, an elongation es% (thickness 2.1μ), and a strength of 27.4 to 9/d.
The elongation was 103% (thickness 26μ).

For comparison, the above and P
When biaxial stretching was carried out at K1111 under the same conditions,
The highest magnification was about 2.5 times in both the vertical and horizontal directions, and at higher magnifications, the film frequently broke.

(Comparative Example-1) Examples-2 to -6 A predetermined amount of the imide compound shown in Table IK was triblended with 100 parts of polyethylene terephthalate chips of Kyogenchou 1.10, and the resulting mixture was triblended using an extruder. Temperature approximately 275℃.

Melt extrusion with an average residence time of about 5 minutes 1 quenching to a thickness of about 2S
An unstretched film of μ was obtained. This unstretched film was superimposed on the polyethylene terephthalate unstretched film of about 400 μm in thickness used in Example-1, and then this was heated at a temperature of 90° C. for 3.5 hours in both length and width. ＠Simultaneous biaxial stretching.

The obtained laminated film was immersed in the indicated organic solvent at a predetermined temperature for a predetermined time to extract and remove the imide compound, and the two films were peeled off and each film was immersed in an organic solvent of a predetermined length for a predetermined time.
It was dried at 50°C for 15 minutes and further heat-treated at 210°C for 2 minutes. Table 1 shows the thickness and physical properties of the obtained film.

Example-7 1-phthalimide-3-7thalimidomethyl-3.5
．． 120 parts of S-)limethylcyclohexane were melted at 240°C in a nitrogen stream, and 10 polyethylene terephthalate chips with an extremely low viscosity f of 1.03 were heated to tSO°C.
0 parts were thoroughly mixed and then held at 150'CK for 1 hour to solidify the imide compound, which was further ground to obtain polyethylene terephthalate chips with the imide compound adhered to the surface. After drying the chip at 150°C for 16 hours, 2,2'-bis(@2,2'-bis(
2-oxazoline) O,SS part and 0.25 parts of 2,2'-bis(3,1-benzoxazin-4-one), and use an extruder to extrude the polymer into 7 parts per polymer.
It was melt-extruded through an i-die at 5° C. and an average residence time of about 1 minute, and then rapidly cooled to obtain an unrolled stretched film having a 41 part viscosity of 1.01 and a thickness of about 20 μm. The Misagi Shin film was prepared in Example-
The film was laminated on the polyethylene terephthalate unstretched film having a thickness of about 400 μm used in 1. Then, this was simultaneously biaxially stretched to 3.6 times in the length and width at 90° C. The obtained laminated stretched film was immersed in xylene at room temperature for about 1 minute to extract the imide compound and peel the laminated film. The peeled ultra-thin stretched film was dried at a constant length at 160°C for about 5 minutes, and then heat-treated at 220°C for about 1 minute, resulting in a film with a thickness of 0.7 μm and a strength of 28.8 Y/-1 and an elongation of 82%. A polyethylene terephthalate stretched film was obtained. The film was subjected to gel permeation chromatography (
When the oligomer content was measured by GPC), it was found to be 0.
1 weight or less.

Example-8 318 parts of diphenyl inphthalate, 9 parts of hydroquinone
2.4 parts of bisphenol and 47.9 parts of N,N'-
A polymer composition obtained by melt reaction in the presence of 264 parts of dodecamethylene bisphthalimide and 0.09 parts of antimony trioxide was melt-extruded at 330°C to obtain an unstretched film having a thickness of about 15 μm. Example-1 of the unrefined film
The film was superimposed on the polyethylene terephthalate unstretched film having a thickness of about 400 μm used in 1, and stretched at 70° C. to double the length in the Il and transverse directions. The obtained stretched coffin film was immersed in xylene at room temperature, the polyethylene terephthalate film was peeled off, and the film was immersed in aS xylene for 30 seconds at a constant capacity for edge drying. The resulting film had a thickness of 1.9μ.

The strength was 13.9, 9 parts w, and the elongation was 56 chi.

1lIIlf Applicant Teijin Ltd.

Claims (1)

[Scope of Claims] 1. On at least one side of an unstretched film whose main component is a substantially linear aromatic polyester, under stretching conditions, the unstretched film has the same or higher strength as the unstretched film. Resin films having a large elongation at break are laminated, and then the resulting laminate is heated at least m in one direction K11E so that the thickness of the unstretched film after stretching is 3μ or less.
A method for producing an ultra-thin polyester film that stretches to 41g11. 2. The Misagi stretched film contains 30 to SOO parts by weight of an imide compound represented by the following formula (1) and/or the following formula (II) per part of substantially linear aromatic polyester 1oo11. 4111. The manufacturing method according to claim am1. 3. A patent characterized in that the stretched laminated film is treated with an organic solvent that melts the imide compound and does not substantially attack the aromatic polyester, thereby extracting 90 or more of the imide compound contained therein. A manufacturing method according to claim 1. 4. Claim I, characterized in that the extraction treatment with organic 11 mK is carried out under film constant length or diaphragm shrinkage conditions! Section 3 Method of manufacturing Ie bandits.