DE2441424A1 - BIAXIALLY ORIENTED FILM AND METHOD OF MANUFACTURING THE SAME - Google Patents

Description

Dr. F. Zumsteln sen. - Dr. E. Assmanrr H H I H Z H Dr. R. Koenigsberger - Dlpl.-Phys. R. Holzbauer - Dr. F. Zumstein jun.

PATENT LAWYERS '

TELEPHONE: COLLECTIVE NO. 22 53 41

TELEX 529979 8MUNICH2.

TELEX 529979 BRÄUHAUSSTRASSE 4

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POST OFFICE GIRO ^ACCOUNT:;

MUNICH 91139-809. BLZ 7OO 1OO 80
BANK ACCOUNT: BANKHAUS H. AUFHÄUSER
ACCOUNT NO. 397997, bank code 700 306 OO

P 2118-K 389
6 / hü

TETJIN LIMITED, Osaka / Japan
Biaxially oriented film and method of making the same.

The invention relates to a biaxially oriented film with a high modulus of elasticity in both the longitudinal and transverse directions, but especially in the transverse direction, which consists of a highly polymerized Polyester to at least 90 mole $, which is repeating units from ethylene 2,6-naphthalenedicarhoxylate exist and also relates to a method of making such a film.

Films made from polyethylene ~ 2,6 ~ naphthalenedicarboxylate (PEN in Short form) can be used in many ways, especially as insulating materials, as a base film for magnetic tapes, and similar.

In the case of magnetic tapes, the requirements are in the course of further development to see that thin base films are required. Therefore, films with a high elastic modulus, in particular created in the longitudinal direction, which are very important in the field of base film for audio tapes.

Used in magnetic tapes as the base film for magnetic imaging tapes , particularly in the case of helical scanning, it is necessary that such a base film is from a magnetic image tape not only a high modulus of elasticity in the longitudinal direction, but

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also has a high modulus of elasticity in the transverse direction

(e.g. not less than 70,000 kg / cm). Previously known base films for magnetic tapes, however, have a high modulus of elasticity mainly in the longitudinal direction, and so far there is none Film known, which in particular has a high modulus of elasticity in the transverse direction.

Known base films for magnetic tapes are, for example, biaxially oriented Polyethylene terephthalate pilme and biaxially oriented PEN films that have good physical properties, in particular a high modulus of elasticity. For these films, the highest modulus of elasticity in the transverse direction so far has been approximately

achieved a value of 64,000 kg / cm, but nowadays films are required, which has an even higher modulus of elasticity in the transverse direction exhibit.

The method for producing the biaxial orientation of the PEN film is in particular, for example, in US-PS -J 501 J44 and 3,683,0β0. In these well-known 'films lies the stretch ratio in the longitudinal direction within a higher range than the stretch ratio in the transverse direction.

On the other hand, Belgian patent specification No. 777 the production of insulation material from PEN film in which the stretch ratio in the transverse direction of the PEN film is greater than that The stretch ratio in the longitudinal direction is. The shown stretch ratio in the transverse direction of the PEN film is a maximum of one On the order of four times.

The invention aims to form a biaxially oriented film so that it is both in the longitudinal direction and has a high modulus of elasticity in the transverse direction, but especially in the transverse direction, the film being made of a highly polymerized Polyester, the main structural unit of which is ethylene-2,6-naphthalenedicarboxylate is, beeteht, and also to provide a method for making such a film.

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Furthermore, according to the invention, the above-described biaxially oriented film should have an extremely high elastic modulus in the transverse direction have a high tensile strength both in the longitudinal and transverse direction. Other objects and advantages of the invention are further elaborated below.

According to the invention, a biaxially oriented film is characterized by this from that the film is at least 90 Mo 1- $ 'of a highly polymerized Polyester is preferably at least 95 mol $, the repeating structural units of which are ethylene-2,6-naphthalenedicarboxylate consist of the film in longitudinal

o direction a modulus of elasticity of at least 51,000 kg / cm and a transverse modulus of elasticity of at least

68,000 kg / cm.

In a preferred embodiment of a biaxially oriented film according to the invention, the film has an elasticity

O
modulus of at least 51,000 kg / cm and a tensile strength at

Break of at least 2 000 kg / cm in the longitudinal direction and in the transverse direction

direction has a modulus of elasticity of at least 68,000 kg / cm

and a tensile strength at break of less than 2,800 kg / cm,

According to the invention, such a biaxially oriented film can be produced in that the unstretched film, which consists of a highly polymerized polyester to at least 90 mol $ preferably but consists of at least 95 moles of which the repeating units consist of ethylene-2,6-naphthalenedicarboxylate consist in the longitudinal direction (machine direction) and transverse direction is stretched, the longitudinal stretching be.i a temperature range takes place, which is 10 to 170 C higher than the second Conversion point of the film, the transverse stretching taking place at a temperature range which is 3 ° C to 160 ° C higher than the second transition point of the film, and observing the conditions set out in the following four expressions are:

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(1) M> 2.5,. ■ .- ■■■

(2) 5.5> T > ^. Ο,

(3) T> M, and
(4-) T <- M + 9.5 »

where M is the stretch ratio in the longitudinal direction in relation to the original length of the unstretched film and T is the stretch ratio in the transverse direction in relation to the original width of the unstretched film, and that thereupon the so stretched Film at a temperature range of 170 ° C to 250 ° C Heat is treated.

The term "highly polymerized polyester" as used in accordance with the invention includes not only polyethylene-2,6-naphthalenedicarboxylate (PEN as an abbreviation) of approximately 100 mol #, the repeating unit of which is ethylene-2,6 -naphthalenedicarboxylate, but also from at least 90 Mo 1- $ of the ethylene-2,6-naphthalenedicarboxylate repeating units derived copoyl ester and not more than 10 mol #, preferably not more than 5 mol # of at least one further polyester.

In general, polyethylene becomes 2,6-naphthalenedicarboxylate produced by the fact that naphthalene-2,6-dicarboxylic acid or its functional derivatives with ethylene glycol or its functional Derivatives react in the presence of a catalyst. The reaction conditions and process conditions are known and are for example in GB-PS 6o4073 and US-PS 311,710. When the copolyester is made, one or more suitable comonomers or modifiers are added to the polymerization system added before completion of the reaction to form polyethylene-2,6-naphthalenedicarboxylate and then is the reaction continued until a copolyester is formed.

The comonomer or modifier can be compounded with be a divalent ester-forming functional group. Such a compound consists, for example, of dicarboxylic acids, such as

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e.g. oxalic acid, adipic acid, phthalic acid, isophthalic acid, Terephthalic acid. And naphthalene-1,5-dicarboxylic acid, naphthalene-1 , β-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, succinic acid, Diphenyl ether, dicarboxylic acid and lower alkyl esters of these dicarboxylic acids; Hydroxycarboxylic acids such as p-hydroxybenzoic acid and p-hydroxyethoxybenzoic acid, and lower alkyl esters of these hydroxycarboxylic acids and dihydric alcohols, trimethylene glycol, Tetramethylene glycol, hexamethylene glycol or neopentyl glycol. The polyethylene-2,6-naphthalenedicarboxylate or its modified one The product can have terminal hydroxyl and / or carboxyl groups capped (. Capped ..) with a monofunctional compound such as benzoic acid, benzoylbenzoic acid, benzyloxybenzoic acid or methoxypolyalkylene glycols. The polyethylene-2,6-naphthalenedicarboxylate can with a small amount of at least one polyfunctional compound such as glycerin and pentaerythritol be modified to such an extent that the linearity of the polymer is not completely lost in use goes.

Other polyesters for use in forming the PEN blends are, for example, those components derived from a dicarboxylic acid that are derived from terephthalic acid, isophthalic acid, adipic acid, Succinic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, 4,4-diphenoxyethane dicarboxylic acid, 4,4'-tetramethylene diphenyldicarboxylic acid and functional derivatives thereof are selected and have a glycol component ^ that of ethylene glycol, Trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol and functional derivatives thereof are. The functional derivatives can, for example, be lower alkyl esters of carboxylic acids, such as these in connection with polyethylene-2,6-naphthalenedicarboxylate was listed.

The "highly polymerized polyester" described above has a Intrinsic viscosity of at least 0.35 that of that in orthochlorophenol solvent viscosity measured at 35 ° C was determined. In particular, the polyesters have an intrinsic viscosity from 0.50 to 0.80 preferably if they have excellent physical properties and good stretchability

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own.

In the conventional production of the film by the melt spinning process, the molten polymer is first filtered, to clean it of the dust mixed with the polymer, and then the film is formed by passing the mass through suitable injection molds is extruded. It is known that the dust in the film is detrimental to the quality of such a film.

However, if the melt of the ethylene ~ 2,6-naphthalenedicarboxylate polymer, as this is carried out according to the present invention, in a simple manner by known filter devices, such as metal mesh, is filtered, the unstretched film produced therefrom often breaks under biaxial stretching of great extent as required by the present invention, especially at such a high draw ratio.

Experiments have found that the relationship of the size of the foreign matter contained in the unstretched film has the with the ethylene-Z ^ -napthalinedicarboxylate polymer in the Stretching temperatures are incompatible, causing the film to break during the stretching process is greater than when using the polyethylene terephthalate film.

Further, it has been found that when the unstretched film made of ethylene-2,6-naphthalenedicarboxylate polymer and containing no foreign matter incompatible with the polymer at the below-mentioned stretching temperatures required according to the invention and one having such a size that the particles have a maximum diameter of 35 μπι exceeds, preferably 30 μΐη, of the invention are stretched in accordance with, that is, stretched in the longitudinal direction at a temperature range of about 1O ⁰ C to 170 ⁰ C higher is than the second Transition point of the film and is stretched in the transverse direction at a temperature range which is 5 ° C to 160 ° C higher than the second transition point of the film, wherein

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the conditions have been met in the following expressions 1 to 4 are listed:

(1) M> 2.5. "■■■ '.'.

(2) 5.5> T> 4.0 ''.

(4) t <- κ + 9.5

where M is the longitudinal stretching ratio in relation to the Original length of the unstretched film and T is the transverse stretching ratio with respect to the original Width of the unstretched film "

The resulting film, which has been stretched in both the longitudinal (machine) and transverse directions, is heat treated at temperatures ranging between 170 ^° C. and 250 ^° C., the biaxially oriented film has a longitudinal modulus of elasticity of at least 51,000 kg / cm and a modulus of elasticity in the transverse direction of at least 68,000 kg / cm, which film can be made without breaking during the stretching processes.

The unstretched film of ethylene-2,6-napthalenedicarboxylate polymer, which does not contain such incompatible foreign substances, the size of which exceeds a maximum diameter of each individual particle of 35 μm, preferably 30 μm, can thereby be achieved that the melt of the polymer is passed through a filter whose pore size 35 μπι, preferably 30 μΐη, does not exceed, and that the melt, then for example . Advantageously extruded through T-injection mold will.

The type of filter is not critical, provided the pore size 35 μπι ,. preferably 30 μπι, does not exceed, and sintered metal mesh and wire mesh can be used in a conventional manner.

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The ethylene-2,6 ~ naphthalenedicarboxylate-polymer which is required according to the invention, can before it is formed as an unstretched film containing the third component, such as the matting agent such as titanium _dioxide,: such as a stabilizer, such as phosphoric acid, phosphorous acid esters thereof, hindered phenol and the like, and lubricants such as finely divided silica, quinaclay and the like. If such a third component, which is incompatible with the polymer at the stretching temperatures required according to the invention, in particular the component which is solid at the stretching temperatures, is selected, advantageously none of the particles of the third component have a maximum diameter , the 35th μπι, preferably 30 μκι, exceeds. If such a solid third component is used, none of the particles has an average particle size which exceeds 5 μm, but preferably 3 μm.

In order to also allow transverse stretching at a higher stretching ratio

nis within the range determined by expressions 1 to 4 listed above, evenly without breaking the Film, it is preferable to use the unstretched film with a uniform thickness «,

A determinant of the uniformity of the thickness of a such unstretched film, especially in the transverse direction, the Α value is equal to the difference between the maximum Thickness (μπι) and the minimum thickness (μπι) divided in the transverse direction is through the mean thickness of the film (μπι). According to the According to the invention, the Α value of the unstretched film does not exceed 0.10, but preferably does not exceed 0.07, which is preferred in this range Results are achieved.

The "mean thickness" of the film listed earlier is calculated in the following manner. If the measured width of a non-knitted film is denoted by "L"

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will and the thickness of the same film that at some point (l) is measured along the measured width, denoted by t (l) the mean thickness is given by the following equation:

lf ^L mean thickness = Tj t (- *) de.

According to the invention, the order in performing the biaxial is The stretching process does not matter if the conditions meet the requirements listed above during the stretching process. However, the stretching process is advantageous first in the longitudinal direction and then in the transverse direction.

The stretching operation in the longitudinal direction of the unstretched film is carried out in a temperature range which is 10 ° C. to 170 ° C. higher is the second transition point of the film used, the stretch ratio being the original length of the unstretched Films satisfies expressions 1 to 4 listed above.

The so longitudinally stretched film is now in the transverse direction, in one Temperature range, which is 3 ° C to ΐβθ C higher than the second The transition point of the film, stretched in the transverse direction, but preferably a temperature which is lower is used than the stretching temperature in the longitudinal direction. The stretching process in the transverse direction is continued until the stretching ratio is satisfied by the expressions 2 to 4. · «Das The stretch ratio in the transverse direction should be greater than 4.0X, preferably 4.3X or even greater. Preferably the The stretching process started at a temperature lower than that of the longitudinal stretching process, but after that the stretching ratio reached about three times in the transverse direction, the resulting stretching operation is to be carried out so that the stretching ratio is within the range determined by the expression 2 - 5.5> T> 4.0 - (where T is the stretch ratio

509812/0993 bathroom ORIGINAL

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ratio in the transverse direction relative to the original width of the unstretched film), and the resultant stretching operation is preferably carried out at a temperature range of at least 120 ⁰ C to 16O ° C.

The object of the invention cannot be achieved if the draw ratio in the transverse direction is not more than four times is. However, if the transverse direction draw ratio T still satisfies Expression 2, i.e. 5.5> T> 4.0, as is required according to the invention, and if expression 3 and / or expression 4 is not fulfilled, what is intended can be Product cannot be achieved in terms of breakage, or the film produced exhibits unsatisfactory physical properties Properties or low quality or no uniformity. When the cross direction draw ratio is 5.5X exceeds, breakage of the film occasionally occurs during the stretching process in the transverse direction.

According to the invention, the stretching process in the longitudinal and transverse directions is preferably carried out under such conditions that the expressions 1 ¹ , 2 ', 3 ¹ and 4 ¹ , which are listed below, are satisfied:

. (l) M> 2.5

(2 ¹ ) 5-3>T> 4.3 -

(3) T> M

(Z _1. ') T <- H + 9.5

M and T are used here as the same quantities as defined above.

According to the invention, the biaxially stretched under the conditions listed above film is then heat-treated at temperatures lying within the range 170-250 ⁰ C, preferably between 180 ° to 240 ° C. Thereby he

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the film holds the required dimensional stability and has high Modulus of elasticity, especially in the transverse direction, and holds \ its form required for the application.

The heat treatment can be carried out while the biaxially stretched film as above is stretched. In a particularly preferred embodiment, at a certain stage of the heat treatment, preferably in the last stage, the film may not shrink more than 5% in the transverse direction. Under such conditions films can be obtained which have a low transverse shrinkage.

The film of ethylene-Z ^ -naphthalenedicarboxylate polymer, the biaxially stretched and heat-treated, has an elastic

modulus of at least 51,000 kg / cm and a tensile strength

speed at break of at least 2000 kg / cm in the longitudinal direction and a modulus of elasticity of at least 68,000 kg / cm and a

Tensile strength at break of at least 2800 kg / cm in the transverse direction how it can be determined from the numerical values listed in the tables and determined using the examples. The film has about the same low heat shrinkage as in the case of the known films made from ethylene-2,6-napthalate polymer, regardless of the high stretching ratios of the former having.

The film according to the invention described here, which in particular has a high modulus of elasticity and a high tensile strength in Has a transverse direction and a sufficiently high modulus of elasticity and a sufficiently high tensile strength in the longitudinal direction, represents a whole new kind of film that was previously unknown. The films according to the invention have such special properties are extremely advantageous to use as the base film of magnetic tapes, especially for magnetic imaging tapes. The film can also be used as an adhesive tape if a layer of adhesive is applied to it, the tape

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has the advantage that it is easily cut off in the transverse direction can be. The use of the film according to the invention, however, is limited to the application examples described above not restricted.

In the following the invention will be explained with reference to working examples and control examples explained in more detail, in which the constituents and percentages are percentages by weight is expressed unless other references are expressly referred to in the description.

The measurement methods and calculations of the properties of the film used in the working examples and control examples are the following:

Tensile strength at break, elongation at break and modulus of elasticity i

The mechanical strength characteristics were measured relative in an atmosphere of 23 ⁰ C and 65% relative humidity using an Instron Zugfeßtigkeitsprüfmaschine under the following conditions:

Shape of the sample: rectangular (15 cm long, 1 cm wide) more original

distance between

the restraints: 10 cm Deformation speed: 10 cm / min.

From the measured results, the properties listed above became determined according to the ASTM designation: D882-64T.

V / arm shrinkage

A film having the original length "Iq" was left for 1 hr. In an air oven at a constant temperature (150 ⁰ C) in an unbound state, and then the measured length was charged with

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"I ₁ " is designated. The heat shrinkage in the longitudinal direction was determined using the following equation:

0 ~ 1

Heat shrinkage = —- x 100 (%)

¹ O ■

The transverse heat shrinkage was measured in a similar manner and manner determined.

Limit viscosity

The intrinsic viscosity was determined by the following equation:

Grenzvi sko si tat = J ^ Sto ¹ ^ ^r

Here, C denotes the concentration in g of the polymer in 100 ml of a solution, 19 is the relative viscosity, measured in the solvent at 35 ^° C. The solvent used in the working examples and control examples was o-chlorophenol.

Stretch ratio

Longitudinal Stretch Ratio is the ratio of the length of the stretched film to the original length of the unstretched one Films called. Correspondingly, the stretch ratio in the transverse direction is given by the ratio of the width of the stretched one Film added to the original width of the unstretched film.

MD, TD

MD means machine direction (or lengthwise direction) and TD means Transverse direction.

A value

The Α value is a parameter for a change in thickness of the unstretched Film in the transverse direction.

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Each 1 cm long strip was from both edges of the sample film and the thickness of the remaining film was measured continuously and automatically over the entire width recorded using an electric micrometer available from Anritsu Electric Co., Ltd. was produced.

From the results, the Α value became according to the following equation determined:

. _w , _ maximum thickness - minimum thickness

medium thickness

The mean thickness was determined by the equation given below when the measured width of the unstretched Film denoted by L and the thickness of the film, measured at a certain point (1), along the measured width, is denoted by t (.l):

mean thickness = J

Average particle size

The average particle size is the arithmetic mean of the maximum and minimum diameters of the sample particles,

Pore size of the filter

The pore size of the filter is determined by the maximum pore diameter determined from the blow test described in British Standard 1752 of 1963.

Examples 1 to 8 and Control Examples 1 to 5 Preparation of the polymer

A reactor equipped with a rectifying column was filled with 5000 parts of dimethyl-Z ^ -naphthalenedicarboxylate,

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2600 parts of ethylene glycol, 3.50 parts of calcium acetate monohydrate and 1.80 parts of antimony trioxide charged / The system was. Long heated about 4 hours, with the temperature rising in the meantime, of 165 ° C to 230 ⁰ C. After the methanol was distilled off, 0.840 parts of phosphorous acid was added to the system. The reaction product was then transported to a polymerization vessel, and the internal temperature gradually rose to 260 ° C. At this temperature, the system was able to react for 10 minutes at normal pressure. Then 49.60 parts of an ethylene glycol paste containing 10% quinaclay (mean particle size 0.8 μm) were added. A further reaction took place for 14 minutes at 250 ⁰ C and 20 mm Hg, and during 170 minutes polymerization at 290 ⁰ C and Oj'5 mm Hg durchgeführt.Ein such a polymer was exhibited Grenzvikosität of 0.63 and a Chinaclay- Concentration of 0.1%.

Making the film

The above-obtained PEN polymer pellets were 3 hours. Dried at a hot air stream of 170 ⁰ C, is melted in an extruder at 298 ⁰ C and filtered through a sintered stainless steel of 20 μπι pore size and onto a casting drum through a T-mold at 60 ⁰ C extruded. The extruded product was quenched and solidified and formed an unstretched film with a thickness of 165 μm. The film was longitudinally stretched by holding it between a pair of rollers having different peripheral speeds, and was heat treated transversely and tensioned. The Α values and the conditions in the stretching and heat treating processes of the unstretched film are shown in Table I.

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16 Table I

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attempt
{No.

example 1

Example 2
Example 3

Example 4
Example 5

Example 6
Example 7

Example B.

Konfcroll-.
toe example '"
JControl example • ^d
Control example ^

A value

O.O5 0.04 0.04 O.O3 0.04 0.04 0.04 O.O5 O.OJ 0.03

Longitudinal stretching

3treckver

age

(fold)

2.9 2.9 3.3 4.0

3.7 3o9 3.8 4.4

3.5

4.2

4.5

^u Tcmp «. ( ⁰ C)

137 137 143

133 140

134 134 137

136 138

Transverse stretching

Btreckver

longevity

(fold)

4.7

4.5
5.0

4.3

4.6
3.8

7, 7,

-Temp

l2:

128. 129 123 128

125 125 129

127 128 125

Heat treatment therapy

240 215 215

180 190 190 I90

215 240 180

The conditions of heat treatment:

In all experiments, the heat treatment was carried out in a stream of hot air performed under tension for approximately 12 seconds.

The conditions in the stretching process used in the control examples 1 to 3 were used, at least one of expressions 1 to 4 does not satisfy.

The properties of a biaxially oriented film thus obtained are shown in Table II.

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■ 17 - Table II

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attempt

3example 3example example 'example 3example example example

example

Control example (oiitroll-

Young's modulus ρ (kg / cr /)

MD

529OO 53IOO 565OO 67400 G2800 58000 54100 62100 56800 64600

■ iontroll

example

'3' 332OO

-—— ■ '- 1 I ■ ■.

TD

75800 83OOO

795OO 745OO 81100 725OO 86200 72.6OO 61900 52400 52IOO

Tensile strength at break

2100 2110 2140 253O 2610 235O. 2200 254O 2380 3290 3630

3OOO 3750 327O 32IO 3350 3IOO 3480 3020 2650 25IO 2380

strain
at break

MD ^:

93
79
77
69
72
69
60
30th
65

37

T])

41

33

48

53 29 65 30 20

63 80

65

Heat shrinkage

MD

0.3 0.6

0.5 0 _o 8

0.7 0.8 1.1 1.9

TD

1.5 1.2 2.2 2.1 2.2 3.0 2.7

0.9 0 * 8

2.5 4.0

1.2 1.8

From Table II it can be seen that the in the working examples obtained film has excellent elastic moduli and tensile strength at break, in particular seen in the transverse direction.

Example 9 Control examples 4 and ' Manufacture of the polymer

A reactor equipped with a recirculation column was with 482.5 parts of dimethyl 2,6-naphthalenedicarboxylate, 13.9 Parts of isophthalic acid, 2600 parts of ethylene glycol, with 3.50 parts Calcium acetate monohydrate, and 1.80 parts of antimony trioxide

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sends. The system was heated for approximately 4 hours, meanwhile the temperature rose from 165 ° C to 230 ° C. After the methanol had been distilled off, 0.840 part of phosphorous acid was added and the reaction product was transported in a polymerization vessel. The internal temperature of the container gradually increased, and "at 260 ⁰ C, the system was allowed to react for 10 minutes under normal pressure, for a further 40 minutes at 275 ° G and 20 mm Hg, and subsequently I50 minutes at 290 ° C under reduced pressure of 0.5 mmHg. Thus, a copolymer having an intrinsic viscosity of 0.60 was obtained.

Making the film

The Copolymerpellets- thus obtained were melted for 3 hours dried in hot air stream at 170 ⁰ C in an extruder at 295 C, by sintered bronze of a pore size of 25> / iMgefiltert, and onto a casting drum at 6O ⁰ C by a T Injection mold extruded. After quenching and solidifying the extruded product, an unstretched film approximately 180 µm thick was obtained which was longitudinally stretched between a couple of rollers of various peripheral speeds, transversely stretched and tensioned heat treated. The Α values of the film used and the conditions of the stretching and heat treatment processes are shown in Table III.

Table III

attempt
No. A-
value Along-
Elongation - Tonp.
( ⁰ C) Cross
stretching Tenp.
Vc) Warmth-
treat-
lung
terap-.
rc) Example 9
Xontroll
example 4-
Control c
example -* 0.04
0.04 '
O.O5 Jtreckver
longevity
(fold) 135
133
133 Stretching
i / receives nii
(fold) I30
I30
I30 220
200
200 3.2
2.0
2.0 4.5
4.5
5.0

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Regarding the heat treatment conditions:

In all the tests carried out, the heat treatment was approximate Under tension in a stream of hot air for 50 seconds carried out.

Control Examples 4 and 5 satisfy the stretching conditions the expression 1 does not.

The properties of the resulting "biaxially oriented film" are summarized in Table IV.

Table IV

Elasticity TD tensile strenght MD TD. strain ( MD fracture Warmth- Ό "" 2 module 75700 at break 253O 3300 at the 81 9 p
(kg / cin) 90500 . p
(kg / cm) 1800 3460 98 TD shrinkage TD attempt
Mr. MD 56 1. Λ Example 9 55300 101500 1740 3790 90 42 MD ' 1. Control L
belspiel 41500 0.6 Control p. 30th 0.3 2. example ^ 40700 0 _o 4

The product of Example 9 has an excellent modulus of elasticity and a tensile strength, especially in the transverse direction. In contrast, Control Examples 4 and 5i show hot which the stretching conditions do not satisfy Expression 1, have a high modulus of elasticity and a high transverse tensile strength on, in the longitudinal direction, however, a markedly lower modulus of elasticity and a lower tensile strength, as shown on the basis the numerical values listed in Table IV can be determined.

Examples 10-15 and Control Examples 6-8

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Manufacture of the polymer

The PEN polymer was prepared in a manner similar to "Examples 1" through 8 and Control Examples Λ "through 3, except that the final state of polymerization" was carried out at 290 ^° C. and 0.5 now Hg for 180 minutes. Such a polymer has an intrinsic viscosity of 0.64 and a quinaclay concentration of 0.1 % .

Making the film

The thus formed PEN polymer pellets were melted dried for 3 hours at 170 ⁰ C in an extruder at 295 ° C, filtered through a sintered stainless steel of a pore size of 20ytt) and onto a casting drum at 60 ⁰ C by a T-injection mold extruded. After quenching and solidifying the extruded product, an unstretched film about 17Qi (^ in thickness was obtained. The film was stretched lengthwise between a couple of rollers of different peripheral speed, then transversely stretched and tensioned heat treated. The Α values of the unstretched film and the stretching and heat treating process conditions are shown in Table V.

Table V

1 A-
value Along- l'emp. Transverse _ ^! Pemp. Warmth-
beiianä- attempt
.No. 0. (νι Stretching
behaved- 143 Streckvei
ratio 126 lung
^te Pc.) Example 10 ο. 04 3.3 138 4.8 130 ISO 'Example 11 0.03 4.1 138 4 5 128 180 Example 12 0.04 3.6 135 5.0 126. 180 Example 13 0.05 4.0 139 4.4 127 190 Example 14 0.05
0.03
0.05
0.03 2.9 143
I34
141
135 5.1 127
126
123 215 Example 15
Control g
example
Control ₇
example '
Control Q 3Λ
4.3
3.5
4.1 4.7
3.2
3.8
3.5 240
240
220
"180

example

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Regarding the heat treatment conditions:

In all of the experimental examples, the heat treatment was for approximately 15 seconds in a stream of hot air for those listed above Temperatures carried out under tension.

In Control Examples 6 to 8, the stretching conditions at least one of Expressions 1 to 4 fail.

The properties of the obtained biaxially oriented film are listed in Table VI.

Table VI

ι
attempt Elasticity
module
ρ
(.ke / cm) TD tensile strenght
at break
ρ
(kg / cm) TD strain
at break
(%) 55 Warmth-
shrinkage
(%) TD JMr. MD 81300 HD 3400 KD 57 ~ ffi5 2.5 Example 10 57IOO 795OO 2580 325O 79 38 1.0 2.2 Example H 67800 '82800 S59O 3580 65 59 0.8 2.4 3example 12 61000 76700 2410 3110 76 30th 0.5 1.9 Example I3 62700 81600 2610 3630 73 56
81
61
63 0.7 1.5 Example 14 53 ^A l-OO 78900
53IOO
6I9OO
59200 2130 3200
2510
2650
2490 81 0.6 1.0
1.1
0.9
2.1 Example 15
Control r
example °
Control
example '
Control
example 8 553OO
69300
56800
735OO 2080
3400
2360
3340 83
50
65
48 0.3
2.5
0.8
3.8

From Table VI it can be seen that the products of the examples have incomparably good moduli of elasticity and tensile strengths in particular have in the transverse direction.

509812/0993

Example 16 Manufacture of the polymer

A reactor equipped with a rectifying column was charged with 485.0 parts of dimethyl 2,6-naphthalenedicarboxylate, 11.9 parts of dimethyl terephthalate, 2,600 parts of ethylene glycol, 3.50 parts of calcium acetate monohydrate, and 1.80 parts of antimony trioxide . The system was. Heated about 4 hours long, while the temperature rise in the reactor of 150 ⁰ C to 23O ⁰ C. After the methanol was distilled off, 0.840 parts of phosphorous acid were added and the reactant product was poured into a. Polymerization container transported. The temperature increased gradually and the system could be operated at 260 ^° C. for 10 minutes under normal pressure, at 250 ^° C. for 40 minutes under a pressure of 20 mm Hg and finally at 290 ^° C. for 150 minutes under a reduced pressure of 0.5 Polymerize mm Hg. Such a copolymer has an intrinsic viscosity of 0.62.

Making the film

The copolymer pellets listed above were in a hot air stream 3 hrs. At 170 ⁰ C dried, melted at 295 ° C in an extruder, ft through a sintered bronze of a pore size of 25, filtered "and. On a casting drum of 60 ⁰ C After quenching and solidifying the extruded product, an unstretched film having a thickness of about 17Q # to and an A value of 0.04 was obtained ⁰ C stretched at a draw ratio of 3 x> 2-fold and stretched in the transverse direction under tension at 129 ° C to a draw ratio of 4.5 times and then 20 seconds heat treated at 220 ⁰ C under tension.
A biaxially oriented film thus obtained faced in the longitudinal direction

a modulus of elasticity of 63 500 kg / cm, in the transverse direction an egg

modulus of elasticity of 76 800 kg / cm, a tensile strength in the longitudinal direction

50981 2/0993

ο
tion "at break of 2,500 kg / cm, a tensile strength" at break

in the transverse direction of 3,090 kg / cm, an elongation at break in the longitudinal direction of 68%, an elongation at break in the transverse direction of 7Ί% i a heat shrinkage in the longitudinal direction of 0.8 % and a heat shrinkage in the transverse direction of 2.2%.

Examples 17-23 and Control Examples 9-12 Manufacture of the polymer

A reactor equipped with a rectifying column was charged with 5000 parts of dimethyl 2,6-naphthalenedicarboxylate, 2600 parts of ethylene glycol, 3-50 parts of calcium acetate monohydrate and 1.80 parts of antimony trioxide. The system was heated for about 4 hours while the temperature rose in the meantime from 165 ° C to 23 ° C. After the methanol had been distilled off, 0.840 parts of phosphorous acid were added and the reaction product was transported into a polymerization vessel. The temperature in the container rose slowly and the system was able to ^{polymerize for 10 minutes at 260 °} C. and normal pressure. Then 64.47 parts of ethylene glycol slurry with a 10% concentration of quinal clay with an average part diameter of 0.8 / itwiem system was added, followed by a reaction for 40 minutes at 275 ° C and 20 mm Hg, and finally it became 13Ο minutes a polymerization carried out at 290 C and 0.5 mm Hg. Such a polymer has an intrinsic viscosity of 0.60 and a quinaclay concentration of 0.13 % .

Making the film

The above-obtained PEN polymer pellets. Dried in a hot air stream of 170 ⁰ C, melted for 3 hours at 296 ° C in an extruder / vigefiltert through a sintered stainless steel of a pore size of 2Q, "onto a casting drum by a T-injection mold extruded and quenched to 6O ⁰ C. Thus, unstretched films of a thickness of about 17Qw ^ but of various Α values were obtained, which are shown in FIG

509812/0993

Longitudinal direction through a couple of rollers with different peripheral speeds were stretched and then stretched and tensioned heat-treated in the transverse direction. The A-Verte of the unstretched film and the conditions of the stretching and heat treatment processes are listed in Table 7.

A-
Value ^; Table VII Along-
Elongation -Temp.
( ⁰ C) '' Transverse stretching. -Temp.l *
( ⁰ C) Temp. 2 **
( ⁰ C) W Ur πίθ
ο e hand- 0.05 3 stretching
h-il '^ nis
(times) ■ 137 Streckver
ratio
(fold) 127 127 lung
temp.
( ⁰ C) attempt
No. 0.05 2.8 143 5.2 127 123 '215 Example 17 0.05 3.3 143 4.8 125 I30 215 Example 18 0.05 3o3 133 4.8 128 128 180 Example 19 0.05 4.1 133 4.5 128 135 180 Example 20 0.03 4.1 133 4.3 128 133 180 Example 21 0.03 3.7 137 5.0 128 128 180 Example 22 0.05
0.03
0.03
0.14 2.9 140
135
135
133 4.6 130
128
118
130 135
128
120
133 240 Example 23 3 * 5
4.3
4.3
4.3
• · 3.8
3.3
3.3
5.5 240
240
180 Control
example 9
Control. _Λ
example ^υ
Control «.
example ⁿ
Control ₁ ο
example ¹ ^

* Temp. 1 is the temperature at which the film is in the transverse direction was drawn to a draw ratio of three times. ** Temp. 2 is the temperature at which the film is threefold the original width was stretched, further to a stretching

509812/0993

244U24

ratio indicated on the left has been stretched.

Heat treatment conditions:

In all of the experimental examples, the heat treatment at the temperatures listed above in a hot air stream was approximately 17 Seconds.

In Control Examples 9 to 11, the stretching conditions fail at least one of Expressions 1 to 4.

The properties of the resulting biaxially oriented films are summarized in Table VIII.

Table VIII

Example 17
Example 18
Example 19
Example 20
Example 21
Example 22

Example 23

Control ^{example y}
Control ^{example υ}
Control example

modulus of elasticity

(kg / cm)

Tensile strength at break

(kg / cm ² )

Elongation, heat at break, shrinkage

52700 56700 57400 68000 63200 61600 53100 56 300 68900 75200

TD

83600 81200 81600

79300

75SOO

82700

73800

61700

52100

57600

2080 2540 2520

2650 2380 2150 2300 .3220 33 ^ 0

3780 3360 3440 3I8O 3OIO 3630 2970 2610 2400 2550

TD I MD

64

63
64
70

70
55
48

31 0.6 61 0.6 51 1.2 60 0.9 62 0.8 31 0.7 61 0.4 65 0.6 78 2.7 73 3.6

TD

1.3

2.6 2.1

1.9 2.1 1.1 0.6

1-3

2.1

509812/0993

From Table VIII it can be seen that the films produced in the examples have a modulus of elasticity far greater than the products of the control examples show, in particular in the right direction.

Control example 12

The pellets of the same polymer that was used in Examples 1 to 8 and Control Examples 1 to 3 were prepared in a hot air stream at 170 ⁰ C for 3 h. Dried, melted in an extruder at 298 ° C, through a wire mesh filter of 80 mesh (Tyler's Mesh, pore size 17 ^ m) filtered and ^{extruded onto a casting drum of 6O 0} C through a T-injection mold.

After quenching and solidification of the extruded product, an unstretched film with a thickness of approximately 170 μm is obtained with a Α value of 0.05. The film was stretched in the longitudinal direction by 5.8 times at 158 ⁰ C, was then stretched to 5.4 times at 152 ⁰ C in the transverse direction under tension, and approximately in hot air stream of 200 ° C for 15 seconds wärmebahandelt . During the transverse stretching operation, the film was broken twice per 50 m length and no practical product could be formed.

509812/0993

Claims (10)

Claims 1. Biaxially oriented film, characterized in that this The film consists of a highly polymerized polyester of at least 90 mol- $, the repeating units of which are ethylene-2,6-naphthalenedicarboxylate exist, and that this film is an elastic modulus of at least 51,000 kg / cm in the longitudinal direction and • p a modulus of elasticity of at least 68,000 kg / cm 'in the transverse direction having. 2. Biaxially oriented film, characterized in that this film is made of a highly polymerized polyester at least 90 mol # consists of the repeating units of ethylene-2,6-naphthalenedicarboxylate exist, and that the film in the longitudinal direction has a modulus of elasticity of at least 51,000 kg / cm and a tensile strength at break of at least 2,000 kg / cm and in the transverse direction, a modulus of elasticity of at least 68,000 kg / cm and has a tensile strength at break of at least 2,800 kg / cm. 5. Biaxially oriented film according to any one of the preceding claims 1 or 2, characterized in that this film forms the base film in a magnetic tape. 4. Biaxially oriented film according to claim 1 or 2, characterized in that that this film forms the base film in an adhesive tape. 5.! Procedure for producing the biaxial film with a \ J 2 ^ Modulus of elasticity of at least 51,000 kg / cm in the longitudinal direction and a modulus of elasticity of at least 68,000 kg / cm in the transverse direction, characterized in that the unstretched film, which is made of a highly polymerized polyester to at least 90 mole $ consists of the repeating units of ethylene-2,6-naphthalenedicarboxylate are stretched both in the longitudinal direction (machine direction) and transverse direction, with the longitudinal 509812/099 3 .28- 244H24 Is carried out stretching at a temperature range of to 10 ⁰ C to 170 C higher is than the second transition point of the film, and wherein the transverse stretching is carried out at a temperature range which lies at J ⁰ C to 16O ° C higher than the second transition point of the film wherein both of the stretching operations are carried out under conditions satisfying the following conditions (1) to (4). (1) η > 2.5 (2) 5.5>T> 4.0
. (3) T> M τ <- η + 9.5 where Π da «stretching ratio in relation to the original length of the unstretched film in the longitudinal direction and T denotes the stretching ratio in relation to the original width of the unstretched film, and this is then:
is heat treated. and then the biaxially oriented film at 170 to 250 ^° C 6. The method according to claim 5> characterized in that the .unstretched film is first stretched in the longitudinal direction and then is stretched in the transverse direction. 7. The method according to claim 5 or 6, characterized in that the unstretched film does not contain any foreign matter that could interfere with the Highly polymerized polyesters are incompatible at the stretching temperatures listed, the particle size of which is a maximum Diameter of 35 microns. 8. The method according to claim 5 or 6, characterized in that the unstretched film does not contain any foreign matter with the highly polymerized polyester at the stretching temperatures listed are incompatible, and their particle size is a maximum Diameter exceeds JO micrometers. 509812/0993 fe 244 U24 9. The method according to any one of claims 5 to 8, characterized in that that the unstretched film has a Α value of not greater than 0.1, the Α value by dividing the difference of the maximum thickness (in micrometers) and the minimum thickness (micrometers) in the transverse direction of the film through the mean thickness (in microns) of the film is obtained, and the mean thickness is determined by the following equation when the measured Width of the unstretched film with L and the thickness of the film, measured at a certain point (1), along the measured Width is denoted by t (1): 1, -L
Average thickness ⁼ LJ 10. The method according to any one of claims 5 to 8, characterized in that that the unstretched film has a Α value which does not exceed 0.07. 509812/0993 ORIGINAL.