JPH0686536B2 - Biaxially stretched polyketone film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a biaxially stretched polyketone film. More specifically, the present invention is a biaxially stretched thermoplastic polyketone having a linear polymer structure in which a phenylene group is linked via an ether group, a thioether group and a ketone group, which is heat-resistant and difficult. The present invention relates to a film which is excellent in flammability and has good mechanical properties and dimensional accuracy in a wide temperature range.

2. Description of the Related Art In recent years, in the electronics field, the need for materials having heat resistance, mechanical properties and dimensional accuracy superior to those of polyethylene terephthalate (PET) is increasing.
On the other hand, polyimide-based films and aromatic polyamide-based films have been studied, but since they are not thermoplastic, they cannot be extruded, and they are expensive and have the drawback of high hygroscopicity. .

On the other hand, thermoplastic polyetherketones and polyetheretherketones have been investigated as films (Japanese Patent Laid-Open Nos. 60-187530 and 61-37419), but they are inferior in flame retardance and crystallized. Since the rate of conversion is high, it is difficult to form an amorphous raw fabric film, and it is difficult to uniformly perform biaxial stretching, and it is difficult to obtain a uniform biaxially stretched film.

Problems to be Solved by the Invention The object of the present invention is to improve the drawbacks of such conventional films, and in addition to being excellent in flame retardancy and stretchability, heat resistance comparable to polyetherketone or polyetheretherketone. The object is to provide a thermoplastic polyketone film having properties and mechanical properties.

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to develop a thermoplastic polyketone film having the above-mentioned excellent characteristics, and as a result,
It has been found that a film obtained by biaxially stretching a polyketone having a specific molecular weight having a specific linear polymer structure in which a phenylene group is linked via an ether group, a thioether group and a ketone group is suitable for the purpose. The present invention has been completed based on the findings.

That is, the present invention is based on the formula (a) And the structural unit shown by Which is composed of a structural unit represented by, and has a linear polymer structure in which (a) units and (b) units are alternately connected and which is biaxially stretched with a polyketone having an intrinsic viscosity of 0.7 or more, and a tensile strength of 15 kg / mm ² or more, Mojiyurasu 250 Kg / mm ² or more biaxially oriented poly ketone film, and (b) And the structural unit shown by And the unit (c) And the structural unit shown in
An intrinsic viscosity of at least 50 mol% based on the total of units, and having a linear polymer structure in which (a) units and any one of (b) units and (c) units are alternately connected.
Tensile strength of 15Kg /
The present invention provides a biaxially stretched polyketone film having a size of mm ² or more and a modulus of 250 kg / mm ² or more.

The polyketone used as the base material of the film of the present invention is a crystalline thermoplastic resin. The crystal melting point and crystallinity of this polyketone differ depending on the type of constituent unit and its composition ratio. Generally, in the structural unit (a), the compound of the formula (I)
The higher the ratio of the units represented by, the higher the crystal melting point and the degree of crystallinity, and therefore does not include the units represented by (II),
The polymer consisting only of the unit (I) has the highest crystal melting point and crystallinity.

Further, regarding the ratio of the (b) constitutional unit and the (c) constitutional unit, it is important that the (b) constitutional unit is contained in a proportion of 50 to 100 mol% with respect to the total thereof. (B) If the content ratio of the structural unit is less than 50 mol%, the flame retardancy is poor, which is not preferable. This flame retardancy is generally superior as the ratio of the (b) constitutional unit in the (b) constitutional unit and the (c) constitutional unit is higher.

From the viewpoint of heat resistance, mechanical properties, flame retardancy, and the like, preferable polyketones in the present invention include, for example, the structural unit (I)
And the ratio of the structural unit (II) to the molar ratio is 50:50 to 1
00: 0, preferably in the range of 80:20 to 100: 0, and the ratio of the structural unit (III) to the structural unit (IV) is in the range of 50:50 to 100: 0 on a molar basis. Is mentioned.
Particularly when rigidity at high temperature is required, the structural unit (a) contains only the unit (I) and the structural unit (II
It is preferable that the ratio of I) to the structural unit (IV) is in the range of 50:50 to 100: 0 on a molar basis.

In the present invention, the intrinsic viscosity of the polyketone needs to be 0.7 or more, and if it is less than 0.7, the film forming ability is poor and the physical properties of the obtained biaxially stretched film are deteriorated. Further, if this value is too large, biaxial stretching becomes difficult, so the preferred intrinsic viscosity is in the range of 0.7 to 1.5.

The polyketone is, for example, 4,4′-dihaloterephthalophenone or 4,4′-dihalobenzophenone or both, 4-hydroxythiophenenol or 4-hydroxythiophenenol and hydroquinone, and diphenylsulfone. , Xanthone, benzophenone, etc., in the presence of alkali such as potassium carbonate, usually 20
It can be produced by polymerization at a temperature in the range of 0 to 400 ° C, preferably 250 to 350 ° C (Japanese Patent Application No. 59-264145).
No. 59-264608 etc.). At this time, copolymers having various monomer sequences can be obtained by controlling the addition order of the monomers.

Regarding the control of the molecular weight and the stabilization of the terminal group, the object can be achieved by the molar ratio of the monomers to be reacted, the polymerization time, the use of the terminal stabilizer and the like.

On the other hand, regarding the film forming method of the film, first, it is necessary to prepare an unstretched amorphous film by a melting method, and for this, an extrusion molding method or a press molding method using a T die or the like is used, After forming, it is rapidly cooled to form an amorphous film. At this time, the melting temperature of the polymer is preferably in the range of not less than the crystal melting point of the polymer and not more than 100 ° C. higher than the crystal melting point. Further, in order to produce a transparent amorphous film, it is desirable that the cooling rate is 5 ° C./sec or more. If the cooling rate is too slow, the film becomes crystallized and becomes opaque, and it becomes difficult to perform uniform stretching. As the rapid cooling method, a method of introducing the film into cold water, ice, or cold air, a method of continuously cooling with a chill roll whose temperature is set to a predetermined cooling rate, and the like are used.

The polyketone used in the present invention is characterized in that it is easier to obtain and has better stretchability than polyetherketone or polyetheretherketone.

The amorphous film thus obtained is rolled at a temperature in the range from the glass transition temperature of the polymer to 210 ° C.,
The intended biaxially stretched film can be obtained by sequential biaxial or simultaneous biaxial stretching at an area magnification of 3 times or more, preferably 5 times or more by a tenter or tube method.
If the area magnification is less than 3 times, a film having desired strength and Young's modulus cannot be obtained. The optimum stretching speed varies depending on simultaneous stretching and sequential stretching even for the same polymer, and depends on the composition (structural unit) of the polymer.
Optimum conditions exist for the stretching method, and appropriate conditions are selected.

The stretched film thus obtained is preferably heat-fixed in order to make it even better. This heat setting is performed at a temperature in the range of 150 ° C. to the melting point of the polymer, and the higher the melting point, the higher the heat setting temperature is desirable. The heat setting may be performed under tension or contraction, and the heat setting time is generally about 1 second to 10 minutes.

The biaxially stretched polyketone film of the present invention obtained as described above has a tensile strength of 15 Kg / mm ² or more and a module of 250 Kg / mm ^2.
It has an excellent feature of mm ² or more.

EFFECTS OF THE INVENTION As described above, the biaxially stretched film of the present invention having excellent strength, heat resistance, flame retardancy and dimensional stability can be obtained by selecting the stretching conditions and the conditions of heat treatment performed as necessary. can get.

In particular, the polyketone used as the base material of the film of the present invention has a relatively slow crystallization in the preheating stage of the amorphous film as compared with polyether ketone or polyether ether ketone, and the initial stress during stretching is Low, wide range of optimal stretching conditions such as stretching speed, stretching ratio, temperature,
At the time of stretching, biaxial stretching is extremely easy because uniform stretching is easy and uneven stretching such as necking hardly occurs. In addition, the heat-fixed film of the present invention is characterized in that sufficient stretch crystallization is achieved.

The biaxially stretched polyketone film of the present invention is suitable for, for example, condensers, electric wire coatings, electric / electronic parts such as flexible printed circuit boards, and precision parts such as recording medium bases such as 8 mm video films, floppy disks, and photographic films. Used.

Examples Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The polymer used in the present invention is only dissolved in concentrated sulfuric acid slightly and is insoluble in general organic solvents, so that it is difficult to determine the average molecular weight. Therefore, it has an intrinsic viscosity and is used as a measure of molecular weight.

The physical properties of the polymer were measured as follows.

(1) Intrinsic viscosity Using concentrated sulfuric acid with a density of 1.84 g / cm ² , a solution containing 0.1 g of polymer per 100 cm ^{3 of} solution and a solution containing 0.5 g of polymer per 100 cm ^{3 of} solution were prepared, and the viscosity was 25 ° C. The intrinsic viscosity = {(η _rel ^-1 ) / C} c → o [where η _rel is the relative viscosity, C is the concentration (g / 100 ml), and c → o is (η _rel ^-1 ) / C value was extrapolated to the point where the concentration C was O] (2) Crystal melting point (Tm), glass transition temperature (Tg) DSC (differential scanning) It was measured by a calorimeter) at a heating rate of 10 ° C / min.

In addition, the tensile strength, module and breaking elongation of the film are AS
It was measured at room temperature based on TM882.

Production Example 1 Production of Polymer (A) Polymerization of an equimolar mixture of 4,4′-difluoroterephthalophenone and p-hydroxythiophenenol in the presence of potassium carbonate in a diphenyl sulfone solvent at 320 ° C. for 4 hours. Then, the terminal was stabilized to obtain a polymer (A) in which the structural unit (I) and the structural unit (III) having an intrinsic viscosity of 0.92 were alternately linked. This product had a crystal melting point of 358 ° C and a glass transition temperature of 152 ° C.

Production Example 2 Production of Copolymer (B) 4,4'-Difluoroterephthalophenone 1 mol and p-hydroxythiophenol / hydroquinone molar ratio 70/30
1 mol of the monomer mixture of
A structural unit (I) having an intrinsic viscosity of 1.05, which is polymerized in a diphenyl sulfone solvent at 300 ° C. for 4 hours to stabilize the terminal.
And a structural unit (III) or one of the structural units (IV) are alternately linked, and the molar ratio of the structural unit (III) and the structural unit (IV) is 70:30 (B) ) Got. This product had a crystal melting point of 359 ° C and a glass transition temperature of 153 ° C.

Production Example 3 Production of Polymer (C) Polymerization of an equimolar mixture of 4,4'-difluorobenzophenone and p-hydroxythiophenenol in the presence of potassium carbonate in a diphenyl sulfone solvent at 290 ° C for 4 hours. Then, the end was stabilized to obtain a polymer (C) in which the structural unit (II) and the structural unit (III) having an intrinsic viscosity of 0.96 were alternately linked. This product has a crystal melting point of 276 ° C and a glass transition temperature of 142.
It was ℃.

Production Example 4 Production of Copolymer (D) 4,4′-Difluoroterephthalophenone / 4,4′-difluorobenzophenone 1 mol of a monomer mixture having a molar ratio of 80/20 and 1 mol of p-hydroxythiophenoenol And in the presence of potassium carbonate in a diphenyl sulfone solvent at 300 ° C
Polymerization was carried out for 3 hours, and one of the constitutional unit (I) and the constitutional unit (II), which had a terminal stability and a viscosity of 0.82, and the constitutional unit (III) were alternately linked, and the constitutional unit (I) A copolymer (D) having a molar ratio with the structural unit (II) of 80:20 was obtained. This product has a crystal melting point of 323 ° C and a glass transition temperature of 149.
It was ℃.

Example 1 The polymer (A) was press-molded at 400 ° C. and put into ice to obtain a transparent amorphous film. The thickness of the film
It was 200 μm.

Using a test tenter biaxial stretching machine (manufactured by Iwamoto Seisakusho Co., Ltd.), the film was simultaneously biaxially stretched at 180 ° C. in both lengthwise and widthwise directions of 2.5 times. The stretching speed was 2000% / min.

Fix the obtained stretched film on a metal frame, 300 ℃
After heat setting for 1 minute, an extremely transparent film having a density of 1,320 g / cc was obtained.

The tensile strength of this film is vertical 28Kg / mm ² , horizontal 25Kg / mm ² , modular (300%) vertical 360Kg / mm ² , horizontal 370Kg / mm ² , breaking elongation 51% vertical, 49% horizontal, The glass transition temperature from Tan δ measured using Vibron was 207 ° C.

The figure shows the values of E ′ and Tan δ. In the figure, (1) is a biaxially stretched film based on the polymer (A), and (2) is
It is a biaxially stretched film based on PEEK 45G (manufactured by ICI). As is clear from the figure, the biaxially stretched film of the present invention is a biaxially stretched film (density 1.317 g / cc, made of PEEK 45G (ICI Co., Ltd.) prepared by the same method.
Rigidity at high temperature was higher than Vibron Tg184 ℃).

Further, the film of the present invention had a shrinkage rate of 0.3% in the vertical direction and 0.3% in the horizontal direction at 180 ° C. for 5 minutes.

Further, according to JIS K 7201, when the oxygen index was measured by a candle combustion tester (manufactured by Toyo Seiki) using a sample having a film thickness of 130 μm, the film of polymer (A) was
29.5%, PEEK 45G (made by ICI) has 2 films
It was 3.5% and it was revealed that the polymer (A) film of the present invention was excellent in flame retardancy.

Examples 2 to 4 Using the amorphous films of the polymers (B), (C) and (D), biaxially stretched films were prepared under the stretching conditions and heat setting conditions shown in Table 1. The properties of the obtained film are shown together in Table 1.

Examples 5 to 8 Using the amorphous film of the polymer (A), biaxially stretched films were prepared under different biaxial stretching conditions and heat setting conditions from those in Example 1. The film forming conditions and the characteristics of the obtained film are shown in Table 2.

Comparative Example 1 A polymer having an intrinsic viscosity of 0.55 manufactured by the same method as that of the polymer (A) was tried to be biaxially stretched by the same method as in Example 1, but the strength was weak and uniform stretching was difficult. It was

[Brief description of drawings]

The figure shows the temperature and E'in the film of Example 1 according to the present invention and the film based on PEEK 45G (manufactured by ICI Corporation).
3 is a graph showing the relationship between the tan and Tan δ. In the figure, (1) is the film of the present invention, and (2) is the film of PEEK 45G.

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Claims (2)

[Claims] 1. A formula And the structural unit shown by Which is composed of a structural unit represented by, and has a linear polymer structure in which (a) units and (b) units are alternately connected and which is biaxially stretched with a polyketone having an intrinsic viscosity of 0.7 or more, and a tensile strength of 15 kg / mm ² or more, Mojiyurasu 250 Kg / mm ² or more biaxially oriented poly ketone film. 2. A formula And the structural unit shown by And the unit (c) And the structural unit shown in
An intrinsic viscosity of at least 50 mol% based on the total of units, and having a linear polymer structure in which (a) units and any one of (b) units and (c) units are alternately connected.
Tensile strength of 15Kg /
mm ² or more, Mojiyurasu 250 Kg / mm ² or more biaxially oriented poly ketone film.