JPH06240019A - Polyalkylene terephthalate film and laminated polyalkylene terephthalate film - Google Patents

Abstract

PURPOSE:To obtain a film excellent in heat stability and mechanical characteristics by stretching a composition consisting of a polyalkylene terephthalate, a liquid crystal polyester of principal chain type, and a compound having terminal functional groups. CONSTITUTION:A film obtained by stretching a composition consisting of a polyalkylene terephthalate, a liquid crystal polyester of principal chain type, and a compound having terminal functional groups. As the polyalkylene terephthalate, polyethylene terephthalate is preferably used. The film is free from interfacial separation due to stretching and improved in interfacial compatibility between the polyalkylene terephthalate and the liquid crystal and has excellent physical properties of both the polyalkylene terephthalate and the liquid crystal polyester.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyalkylene terephthalate film having excellent thermal stability and mechanical properties. Stretched polyalkylene terephthalate film particularly used for applications requiring heat stability and mechanical properties among polyalkylene terephthalate films used as substrates for printing substrates, packaging, cards, magnetic recording tapes, etc. It is about.

[0002]

2. Description of the Related Art Polyalkylene terephthalate films such as polyethylene terephthalate films are
It has excellent transparency and mechanical properties and is widely used. However, along with the generalization, the durability under severer conditions has been required. Liquid crystal polyesters, that is, polyesters exhibiting optical anisotropy when melted are those that can satisfy these characteristics, and have been developed for film processing in recent years. However, because it uses expensive raw materials, it cannot be said to be an inexpensive polymer, and because the anisotropy at the time of melting remains as it is after molding, vertical tearing called fibrils occurs and the workability and handleability are poor. there were.

On the other hand, blending of polyethylene terephthalate and the like with a liquid crystalline polyester has been studied in order to maintain the processability and mechanical properties of polyalkylene terephthalate and to improve the thermal stability and mechanical properties.

However, polyalkylene terephthalates such as polyethylene terephthalate and liquid crystal polyesters are generally incompatible, so that a polymer interface is formed. Therefore, if stretching is performed at a temperature lower than the melting point of polyalkylene terephthalate, cracks are generated at the polymer interface, resulting in thermal stability. Properties and mechanical properties were not sufficiently improved.

That is, a good liquid crystal polyester and a polyalkylene terephthalate film blended with the polyalkylene terephthalate are produced by taking advantage of the excellent processability, transparency and mechanical properties of the polyalkylene terephthalate and the thermal stability and mechanical properties of the liquid crystal polyester. Did not exist.

[0006]

The present invention provides a good polyalkylene terephthalate film film utilizing the excellent processability, transparency and mechanical properties of polyalkylene terephthalate and the thermal stability and mechanical properties of liquid crystal polyester. A polyalkylene terephthalate (a), a main chain type liquid crystal polyester (b), and a compound (c) having functional groups at both ends to obtain a polyalkylene terephthalate film. is there.

The polyalkylene terephthalate referred to in the present invention is a polymer whose main components are obtained by polycondensation of alkylene glycol and terephthalic acid. The alkylene glycol is represented by ethylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol, polyalkylene glycol and the like. The main components are alkylene glycol and terephthalic acid units of 80 mol% or more, preferably 9
It means that it is 0 mol% or more. Of course, within the above range, other types of diol components (for example, cyclohexanedimethanol, etc.) or other types of dicarboxylic acid components (for example, isophthalic acid, naphthalenedicarboxylic acid phthalate,
Adipic acid, sebacic acid, etc.) may be copolymerized.
Specifically, for example, polyethylene terephthalate (P
ET), polytetramethylene terephthalate (PB
T), polyethylene-2,6-naphthalene dicarboxylate (PEN) and the like. In the case of the present invention, PET is particularly preferable. In addition, various known additives such as antioxidants, antistatic agents, inorganic particle fillers, organic particle fillers, and coloring agents may be added to the polyalkylene terephthalate.

Without limiting the invention, the carboxy end groups of polyalkylene terephthalate may be from 1 to 100.
It is good that it is (eq / ton). Preferably 5 to 50
(Eq / ton), and more preferably 10 to 30.
(Eq / ton).

The constituent component of the main chain type liquid crystal polyester referred to in the present invention comprises one or more of aromatic dicarboxylic acid and alicyclic dicarboxylic acid, one of aromatic diol and alicyclic diol, or One or more, one or more aromatic hydroxycarboxylic acids, one or more aromatic thiolcarboxylic acids, one or more aromatic thiolphenols, It is selected from the group consisting of one or more of aromatic hydroxyamine and aromatic diamine. Although not included in the combination of the above components, aromatic polyazomethine and liquid crystalline polyester carbonate are further included as the main chain type liquid crystalline polyester. Preferred are carboxylic acid ester-based liquid crystal polyesters containing carboxylic acid derivatives such as More preferred is a main chain type liquid crystal polyester composed of the following structural units.

[0010]

[Chemical 1]

[Chemical 2]

[Chemical 3]

[Chemical 4] (Here, n1, n2, n3, and n4 mean the mol% value of each structural unit, and the total is 100.)

The main chain type liquid crystal polyester used in the present invention contains an aliphatic diol in the same molecular chain in addition to the above-mentioned constituents as long as the main chain type liquid crystal polyester exhibits liquid crystallinity. Good. The liquid crystallinity is a polymer having optical anisotropy when melted. The anisotropy during melting can be confirmed by a polarization inspection method using a crossed polarizer. More specifically, using a Leitz polarization microscope,
It can be confirmed by melting the sample placed on the Leitz hot stage and observing it under a nitrogen atmosphere at a magnification of 40 times. Liquid crystalline polyester is about 1.0 when dissolved in pentafluorophenol at a concentration of 0.1% by weight at 60 ° C.
A material having a logarithmic viscosity (IV) of 12 dl / g is preferable. Preferably about 3.0-12 dl / g logarithmic viscosity (IV)
Is.

The addition of the main chain type liquid crystal polyester has the effect of improving the thermal stability and mechanical properties of the polyalkylene terephthalate.

The compound having functional groups at both ends is a compound having two functional groups having some reactivity and affinity with polyalkylene terephthalate. With one functional group, it is difficult to improve the affinity of two types of polymers, and with three or more functional groups, gelation tends to occur. A functional group that reacts with the carboxy terminal of polyalkylene terephthalate is preferred. A glycidyl group is preferable as the functional group, and a group having a glycidyl ether ester or a glycidyl ester is further preferable. In particular, a compound in which both end functional groups are glycidyl ether ester groups containing p-hydroxybenzoic acid is preferable. The molecular weight is about 100-4000
A low molecular weight product is preferred. Preferably molecular weight 250-1
It is 000. In the case of a glycidyl compound having both terminals, its epoxy equivalent is 100 to 600 g / eq, preferably 150 to 250 g / eq.

The continuous medium of the film is polyalkylene terephthalate, and the dispersion component is a main chain type liquid crystal polyester. Component The amount of the main chain type liquid crystal polyester (b) used in the present invention is 2 to 59% by weight, preferably 5 to 30% by weight. When the amount added is less than 2% by weight, it is difficult to improve the thermal stability and mechanical properties of the polyalkylene terephthalate film of the present invention. On the other hand, when the amount of the main chain type liquid crystalline polyester (b) added exceeds 59% by weight, the continuous medium of the film is unlikely to be polyalkylene terephthalate, and the anisotropy due to the properties of the main chain type liquid crystalline polyester remains unchanged. Workability deteriorates because it remains after molding.

The compound having a functional group at both ends is 0.1 to 1
0% by weight is good. If the amount is less than 0.1% by weight, the affinity or adhesiveness of the polymer interface between the polyalkylene terephthalate and the liquid crystal polyester is not sufficient, so that the polyalkylene terephthalate, which is the object of the present invention, has excellent processability and transparency. However, it does not become a good polyalkylene terephthalate film that takes advantage of mechanical properties, thermal stability of liquid crystal polyester, and mechanical properties. When it exceeds 10% by weight, the melt viscosity of the mixed composition is increased and extrusion becomes difficult.

A film of the composition of the present invention is formed by stretching. Stretching is carried out under the condition that ordinary polyalkylene terephthalate is stretched.

A method for producing the polyalkylene terephthalate film of the present invention will be described, but the method is not limited to such a method.

As the main chain type liquid crystal polyester, a liquid crystal polyester having the following structural unit was used.

[0019]

[Chemical 5]

[Chemical 6]

[Chemical 7]

[Chemical 8] (Here, n1, n2, n3, and n4 mean the mol% value of each structural unit, and the total is 100.)

Furthermore, polyethylene terephthalate and a compound containing glycidyl groups at both ends are mixed, thoroughly mixed, dried and fed to an extruder heated to a temperature of 270 to 300 ° C., and a drum surface temperature is set to 10 to 60 ° C. Static electricity is adhered to the cooled drum to solidify by cooling, and the unstretched film is guided to a roll group heated to 75 to 120 ° C. and longitudinally stretched in the machine axis direction by 2.0 to 5.0 to 20 to 50 ° C. Cool with rolls. The uniaxially stretched film obtained at this time may be subjected to corona discharge treatment for coating.
Next, both ends of this uniaxially stretched film are guided to a tenter while holding both ends with clips, and transversely stretched in a direction perpendicular to the machine direction in an atmosphere heated to 90 to 140 ° C. The stretching ratio is 2 to 5 times in each of the length and width, and the area ratio is preferably 6 to 15 times. If the area ratio is less than 6 times, the mechanical properties will be insufficient, and conversely, if it exceeds 15 times, tearing will tend to occur during stretching and the film formability will tend to be poor.

In order to impart the flatness and dimensional stability of the biaxially stretched film in this way, the film thickness in the tenter is 150-150.
It is heat-set at 230 ° C., uniformly cooled slowly, then cooled to room temperature and wound. At the time of heat setting, it is possible to add a relaxation of 10% or less in order to reduce the heat shrinkage rate. Thus, the polyester film of the present invention is obtained.

Alternatively, as described above, the polyalkylene terephthalate film may be first produced under the above conditions, and the coating layer may be laminated thereon by melt extrusion or coating.

The polyalkylene terephthalate film of the present invention contains calcium carbonate, amorphous zeolite particles, anatase type titanium dioxide, calcium phosphate,
Fine particles of silica, kaolin, talc, clay or the like may be used in combination. The addition amount of these is preferably 0.005 to 1 part by weight with respect to 100 parts by weight of the polyalkylene terephthalate composition. In addition to such fine particles,
In the polycondensation reaction system of polyalkylene terephthalate, fine particles precipitated by the reaction between the catalyst residue and the phosphorus compound can be used together. As the deposited particles, for example, those composed of calcium, lithium and phosphorus compounds, or
Examples thereof include those composed of calcium, magnesium and phosphorus compounds. The content of these particles in polyalkylene terephthalate is polyalkylene terephthalate 1
It is preferably 0.05 to 1 part by weight with respect to 00 parts by weight.

[0024]

[Measurement of physical properties and evaluation method of effect]

1. Average Diameter (a) and Shape Factor of Dispersion A cross-section of the unstretched film cut in the machine direction (MD) was taken with a scanning electron microscope at a magnification of 1000 to 5000 times, and at least 100 pieces in the specified thickness range were taken. The above incompatible polymer dispersion is applied to an image analyzer, and the diameter distribution of circles corresponding to the area of the dispersion is determined. The area average diameter of this distribution is the average diameter of the dispersion (dispersion diameter).
And Further, the ratio of 100 major axis / minor axis is the shape factor of the dispersion.

2. Heat shrinkage rate The film is cut in MD direction or TD direction to a width of 10 mm and a length of 300 mm, marked at 200 mm intervals, fixed to a support plate under constant tension (5 g), and then the original length a (mm) of the marking interval is measured. . Next, a load is applied using a clip of 3 g and the treatment is performed for 30 minutes while rotating in a hot air oven at 190 ° C., and the marking interval b (mm) is measured in the same manner as the measurement of the original length. The heat shrinkage rate is calculated by the following formula, and the average value of 5 is used.

Thermal shrinkage (%) = (ab) / a

3. MIT Flex Resistance Test According to JIS-P-8115, the test was performed until the film was broken, and the number of times was measured. The maximum was 10,000 times.

4. Measurement of carboxy terminal amount of polyester A sample of 0.5 g is taken, dissolved in 10 ml of o-cresol, and measured by potentiometric titration with potassium hydroxide (0.1 N) according to the method of Maurice et al.

5. Intrinsic viscosity (η) of polyester Dissolved in o-chlorophenol according to a known method and measured at 25 ° C. 6. Mechanical properties ASTM for tensile Young's modulus, breaking strength and breaking elongation
-Measured according to D-882-81 (method A).

[0030]

EXAMPLES The present invention will be described based on examples.

Example 1 As a main chain type liquid crystalline polyester, JP-A-63-275 was used.
According to the description of Example 1 in Japanese Patent No. 628, the following main chain type liquid crystal polyester was polymerized and then extruded with nitrogen to obtain a chip-shaped main chain type liquid crystal polyester.

[0032]

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12] Here, n1 was 10 mol%, n2 was 67 mol%, n3 was 13 mol%, and n4 was 10 mol%. The liquid crystal polyester had a number average molecular weight of 16,000.

Polyethylene terephthalate (PET) 8
9% by weight, main chain type liquid crystal polyester 10 prepared above
Wt% and 1% by weight of polypropylene glycol diglycidyl ether (epoxy equivalent 320 g / eq, "Glycier" PP-300, Sanyo Kasei Co., Ltd.) are mixed and extruded with a twin screw vent heated to 270 to 300 ° C. Extrusion was performed while degassing and drying with a vacuum pump so that the vent pressure was 10 (mmHg) from the machine, and a sheet was formed from a T die. Further, this film was cooled and solidified by a cooling drum having a surface temperature of 25 ° C., led to a roll group heated to 80 to 100 ° C., longitudinally stretched 3 times in the machine axis direction, and cooled by a roll group of 25 ° C. Subsequently, both ends of the longitudinally stretched film were guided to a tenter while gripping both ends with clips, and transversely stretched 3.6 times in a direction perpendicular to the machine axis direction in an atmosphere heated to 115 ° C. 220 in the tenter
The film was heat-set at 0 ° C., uniformly cooled and then cooled to room temperature to obtain a film having a winding thickness of 100 μm. The physical properties of the obtained film are shown in Table 1.

Example 2 In Example 1, 10% by weight of LCP-100E (manufactured by Idemitsu Petrochemical Co., Ltd.) was used in place of the main chain type liquid crystalline polyester, and EX was used as a compound having functional groups at both ends.
1% by weight of 721 (epoxy equivalent 165 g / eq, diglycidyl phthalate, manufactured by Nagase Kasei Co., Ltd.) was used to obtain a film in the same manner as in Example 1. The physical properties of the obtained film are shown in Table 1.

Comparative Example 1 A film was obtained in the same manner as in Example 1, except that 90% by weight of polyethylene terephthalate (PET) and 10% by weight of the main chain type liquid crystal polyester used in Example 1 were used.
The physical properties of the obtained film are shown in Table 1. Without addition of a compound having functional groups at both ends, the physical properties of the film were not excellent.

[0036]

[Table 1]

[0037]

The polyalkylene terephthalate film of the present invention has the following effects.

By adding a liquid crystal polyester and a compound having a functional group at both ends to the alkylene terephthalate, the interfacial affinity between the polyalkylene terephthalate and the liquid crystal polyester is improved by stretching without interfacial peeling by stretching. A stretched polyalkylene terephthalate film having excellent physical properties of alkylene terephthalate and liquid crystal polyester can be obtained. Specifically, interfacial affinity improves thermal stability and mechanical properties.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display area B29L 9:00 4F C08L 67:00

Claims (6)

[Claims] 1. A polyalkylene terephthalate (a),
A polyalkylene terephthalate film obtained by stretching a composition comprising a main chain type liquid crystal polyester (b) and a compound (c) having functional groups at both ends. 2. The polyalkylene terephthalate film according to claim 1, wherein the polyalkylene terephthalate (a) is polyethylene terephthalate. 3. The polyalkylene terephthalate film according to claim 1, wherein the functional groups at both ends of the compound (c) having functional groups at both ends are glycidyl groups. 4. The polyalkylene terephthalate film according to claim 1, wherein the both-end functional groups of the compound (c) having both-end functional groups are glycidyl ether ester groups containing p-hydroxybenzoic acid. 5. The polyalkylene terephthalate film according to claim 1, wherein the carboxy terminal group of the polyalkylene terephthalate (a) is 1 to 100 (eq / ton). 6. A laminated polyalkylene terephthalate film comprising the polyalkylene terephthalate film according to claim 1 and a coating layer.