JPS5942611B2 - Method for producing polyphenylene sulfide film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a film containing polyphenylene sulfide (hereinafter referred to as PPS) as a main component.

Conventionally, film molded products containing PPS as a main component are produced by melting the raw material and pressing it through a slit-shaped die.

It was produced by cooling, solidifying, and then heat-treating or stretching heat-treating. However, in such conventional film manufacturing methods, when the edges of the film, that is, the edges other than the predetermined width that will become the product, are collected as scrap and the scraps are mixed into the raw material and reused, gel-like foreign substances peculiar to PPS are generated. This caused deterioration of film properties.

Moreover, even without mixing this waste, the obtained film is
It had the disadvantage of poor mechanical properties under low-temperature conditions (cold region). Furthermore, film forming methods that include a stretching process are also plagued by film breakage during stretching due to gel-like foreign matter. The purpose of the present invention is to eliminate the drawbacks of the conventional methods and provide a method for industrially and extremely efficiently manufacturing PPS films that have excellent heat resistance and low-temperature toughness while recycling "waste". This is what we intend to provide.

In order to achieve the above object, the present invention has a melt flow value M
A thermoplastic resin composition mainly composed of polyphenylene sulfide with a high polymerization degree of 10≦M≦130 is melted, extruded through a slit-shaped die, cooled and solidified to form a film,
Next, the lower limit temperature T is 275°C or lower and is determined by the following formula.

The present invention is characterized by a method for producing a polyphenylene sulfide film, which is heat-treated for a fixed length at the above temperature for 1 second to 100 seconds. T0=1.3M+100 "High polymerization degree PPS" as used in the present invention means that 90 mol% or more of the repeating units of the polymer have a structure represented by the formula +05, and the melt flow value (AST
According to MD-1238-70, using a load of 5 kg,
The value measured at 315.6°C (below 600) and expressed in g/10 minutes is between 10 and 130 (more preferably 15
100).

The remaining less than 10 mol% of the repeating units of the polymer can be comprised of those having the following structural formula. Such high polymerization degree PPS includes thiosulfate,
From thiourea, thioamides, elemental sulfur, carbon disulfide, carbon oxysulfide, thiocarbamates, monothiocarbonates, dithiocarbonates, trithiocarbonates, mercabutanes, methicaptides, sulfides, phosphorus pentasulfide, and alkali metal bisulfides. Polymerizing at least one selected sulfur compound, at least one P-dihalogenbenzene, at least one base, at least one organic amide, and at least one alkali metal carboxylate. It can be obtained by

Note that even if the melt flow value of the polymerized polymer exceeds 130, the value is reduced to 130 or less by contacting the polymer with a high temperature gas containing oxygen (hereinafter referred to as
However, in this case, the melt flow value before precuring must be 1500 or less. If the melt flow value of the polymer is less than 10, the polymer will have poor fluidity during melting, making subsequent melt extrusion operations difficult.
Furthermore, if the melt flow value exceeds 130, it becomes difficult to recycle the "waste" due to the generation of gel, and furthermore, the toughness of the produced film at low temperatures is significantly impaired. The same applies when the melt flow value before precuring exceeds 1500. There is no perfect relationship between melt flow and polymer melt viscosity, but melt flow 10 to 13
0 corresponds to a melt viscosity of 1 to 20,000 voids to 1 to 2,000 voids at approximately 300° C. and a shear rate of 200 (seconds).

Regarding the degree of polymerization, it is not easy to measure because PPS does not dissolve at all in general organic solvents at room temperature, and it varies greatly depending on the copolymer composition, degree of crosslinking, etc., so the exact value is unknown, but it is approximately 50. It is about 1000. In addition to the above-mentioned high degree of polymerization PPS, the thermoplastic resin composition used in the present invention contains a polymer composition (for example, polyarylene sulfide,
(polyarylate, polyester, polyamide, polyethylene, polystyrene, polycarbonate, polysulfone, polyethersulfone, fluorine-containing polymer, polyimide, etc.) or/and about 10 wt% or less of organic or inorganic filler (for example, glass fiber, carbon fiber, (talc, titanium oxide, silicon oxide, carbon black, clay, mica, asbestos, metal powder, etc.)
can include. Additionally, additives such as antioxidants, heat stabilizers, lubricants, nucleating agents, and ultraviolet absorbers can be added to the extent that they are usually added. If the resin composition contains other polymers, fillers, etc. in amounts exceeding the above range, the toughness of the resulting film at low temperatures will be impaired.

In the present invention, the method of blending other compositions with high polymerization degree PPS is to mix granules, powders, or pellets of each composition into V.
It may be mixed using a mixing device such as a mold blender or spar mixer, and then fed directly to the melt-molding process (or it may be melt-mixed using an extruder, co-kneader, etc., pelletized, and fed to the melt-molding process). Good too.

The PPS composition thus obtained is supplied to a well-known melt extrusion device such as an extruder, and heated to a temperature higher than the melting point of the composition to melt it.

PPS in a molten state is easily oxidized and crosslinked when it comes into contact with oxygen, which is one of the causes of gel formation, so it is most preferable to replace the inside of the hopper of the extruder with an incurable gas such as nitrogen or carbon dioxide. . In addition, when performing melt extrusion using an extruder, 0.01 to 0.5 wtc of a lubricant typified by an organic metal salt is added to the raw resin composition.
By adding f6, shear heat generation in the solid transport zone within the barrel of the extruder is reduced, and as a result, generation of gel peculiar to PPS is suppressed, which is extremely preferable. The molten PPS-based composition is continuously extruded from a slit die (e.g., T-die, circular die, etc.), and then "high polymerization degree PPS" which is the main component of the composition is extruded.
It is forcibly cooled and solidified to a temperature below the glass transition point of PS.

Such forced cooling methods include a method of casting on a drum whose surface is maintained at a temperature below the glass transition point, a method of blowing a gas or liquid at a temperature below the glass transition point, or a method of blowing a gas or liquid at a temperature below the glass transition point. A method such as immersion in a liquid maintained at a temperature below a certain temperature can be used. It is also possible to use a combination of the above methods. In order to effectively achieve the object of the present invention, in the cooling solidification process, the time during which the temperature of the resin is above the glass transition point is 100 seconds or less (preferably 60 seconds or less).
(seconds or less).

Within this range, there is no problem in taking cooling delay means such as bringing the extruded resin into contact with a so-called "hot roll" before forced cooling. If the time involved exceeds 100 seconds,
This promotes the formation of "gel" in the "waste" recycling process, and at the same time impairs the toughness of the produced film at low temperatures. As an example of the most preferable cooling solidification method for the purpose of the present invention, a molten film is cast on a metal drum whose surface is kept below 30°C, and at the same time, an electrostatic charge is applied to the polymer near the contact point between the molten polymer and the drum. , a method (so-called electrostatic application casting method) in which the molten polymer is brought into close contact with the drum surface by Coulomb attraction between the electrostatic charge and the induced charge induced on the drum surface to promote cooling of the polymer. Can be done. We believe that the electrostatic casting method is extremely effective in achieving the present invention; that is, by using this method, the cast resin composition is cooled more rapidly, and the resulting film has a significantly improved flatness. It has been found that as a result of this improvement, favorable results can be obtained in improving the toughness of the final film at low temperatures. In this way, a film-like molded product, which is an intermediate product, is obtained.

The term "film" used in the present invention means a thin leaf-shaped molded product having a thickness of 5 or less. Next, constant length heat treatment is performed for the purpose of strengthening heat resistance.

The term "fixed length heat treatment" as used in the present invention means heat treatment under conditions such that the dimensional change of the film before and after the heat treatment is ±5% or less. The heat treatment in the present invention is carried out by bringing the film to be treated into contact with a stream of heated liquid or gas, or the surface of a solid. The "temperature" and "time" of heat treatment in the present invention are nothing but the temperature and contact time of the heating medium. Specific examples of such heat treatment methods include a method of bringing the material into contact with a heated roll (hereinafter referred to as roll heat treatment method), a method of using a tenter, and a method of blowing hot air onto the roll. The upper limit of the heat treatment temperature in the present invention is
275° C., while the lower limit is equation T where the melt flow value M of the resin composition is a variable.

T determined by =1.3M+100 (10≦M≦130). It is 5.

The lower limit is more preferably set to at least 150° C. in view of the heat resistance of the resulting film. If the temperature of such heat treatment is below the above-mentioned lower limit temperature, the toughness of the produced film at low temperatures will be impaired, and if the temperature is lower than 275
If the temperature exceeds .degree. C., not only will gel be generated when recycling the scraps, but the film to be treated will soften and lose shape retention, making it difficult to carry out the heat treatment by the above method.

It is essential that the heat treatment time in the present invention is 1 second or more and 100 seconds or less, but the optimal time range for the heat treatment is as follows:
Depends on processing method.

For example, the heat treatment time is preferably 1 second to 20 seconds for roll heat treatment, and 5 seconds to 60 seconds for the Denta method. The heat treatment time is 1
If the time is less than 100 seconds, the heat resistance of the produced film will not be sufficiently strengthened, and if the time is more than 100 seconds, it will leave "waste".
During recycling, gel is generated, and the toughness of the produced film at low temperatures is also impaired.

In the present invention, it is essential to perform heat treatment after the melt-extruded resin composition is cooled and solidified to form a film. Later, processing such as lamination or heat fusion with other articles, thermocompression bonding to a metal surface, surface treatment, etc. can be performed.

Also, a molten “composition mainly composed of high polymerization degree PPS”
It is also possible to extrude laminate directly onto other articles. According to the method of the present invention, the generation of gel during recycling of "waste" is significantly reduced, making it possible to recycle "waste" which was virtually impossible in the past, and achieving extremely high industrial yield. The effect is that it is possible to produce a film made of a PPS-based composition.

In addition, the film produced according to the present invention not only has the excellent heat resistance characteristic of PPS, but also has excellent toughness at low temperatures, and is resistant to vibration, repeated expansion and contraction, and bending stress even under low temperature conditions below room temperature. Because of its excellent durability, it can be used in an extremely wide range of applications, including being able to be used outdoors in cold regions, where conventional PPS films cannot be used.

The film produced according to the present invention can be used as an insulating material (for example, a circuit board,
Slot liner, etc.). Next, the method of the present invention will be specifically explained using examples.

The methods for measuring and evaluating the characteristic values of the polymers and films used in the Examples below are as follows.

(1) Glass transition point (Tg) and melting point (Tm) were determined by differential thermal analysis.

(2) Melt flow value Measured at 315.6° C. (below 600° C.) using a load of 5 kg according to the method specified in ASTM D-1238-70.

Values are expressed in g/10 minutes.

(3) Tensile strength and elongation Measured using an Instron type tensile tester according to the method specified by JIS Zl7O2VC.

(4) Heat resistance The strength and elongation of the film at 150°C was measured using the method described above.

Further, after the film was aged in a hot air oven at 250° C. for 48 hours, the strength and elongation was measured by the method described above and compared with the strength and elongation before aging. (5) Amount of gel-like foreign matter in the polymer Observed using an optical microscope.

The numerical value is expressed as the number per 100 μm of film thickness and 100 μm of area. (6) Increase in gel due to recycling of "waste" Repeat "waste" recycling 10 times (however, each time, 50wtq6 of the raw resin was used as scrap from the previous time), and then apply the same method as described in (5) Vc. The amount of foreign matter was measured and compared with the case without recycling.

(7) Changes in physical properties due to recycling of “waste” (6)
), the strength and elongation were measured using the method (3), and compared with the case without recycling.

(8) Toughness at low temperature The bending resistance of the film at 0° C. was measured according to the method specified in JISP8ll5 (so-called MIT method).

Example 1 (1) Polymerization of PPS A. 32.6k of sodium sulfide was added to the polymerization autoclave for high polymerization degree PPS (referred to as PPS-A) used in the present invention.
g (250 mol, including 40 wt% of water of crystallization), 100 g of sodium hydroxide, 36.1 kg of sodium benzoate (
250 mol) and 79.2 kg of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were charged, and while stirring, the temperature was gradually raised to 205°C to produce 7.0 t of distillate containing 6.9 kg of water. was removed.

Add 1,4-dichlorobenzene (DCB) to the remaining mixture.
) 37.5 kg (255 mol), and NMP
2O. After adding Okg, the mixture was heated at 265°C for 5 hours. The reaction product was washed 8 times with boiling water and heated to 80°C using a vacuum dryer.
Dry for 24 hours at melt flow 80, Tg 89℃
, a high polymerization degree PPS2l. having a Tm of 280°C. lkg(
A yield of 78%) was obtained.

B. Polymerization of PPS (referred to as PPS-B) for comparison Polymerization was carried out for 2 hours in the same manner as in A above to obtain about 20 kg of dried PPS having a melt flow of 205, Tg of 87°C, and Tm of 281°C.

(2) Melt molding Compositions A and B obtained in the above (l) were each melted at 40 nT.
mφ extruder, melted at 310°C, length 320 m) with a straight lip with a gap of 0.3 mm.
It was extruded from a die, electrostatically cast onto a metal drum whose surface temperature was maintained at 30° C., and cooled and solidified to obtain films A and B having a width of 280 m and a thickness of 50 μm.

(3) Heat treatment Films A and B were heat-treated by contacting them with a heating roll having a surface temperature of 250° C. for 5 seconds (the obtained films are referred to as A-1 and B-1).

On the other hand, for comparison, films A and B were prepared at a surface temperature of 190
The films were heat-treated for 5 seconds with a roll at .degree.

It is clear that the film produced by the method of the present invention produces less gel than other films and has excellent toughness at low temperatures.

Example 2 (1) Polymerization of PPS In the same manner as in Example 1 (1) A, five types of PPS with different melt flows (PPS-C, -D, -E, *I K sample symbol used PPS Heat treatment temperature (0 Kg b /Rnrri: 1-・ A=1 A-2 B-1 B-2 A A B B 7.2 7.4 6.9 7.0 8.9 8.7 8 , 5 8.3 2.4 2.5 2.6 2.4 Conditions for measuring strength and elongation A. Measured at room temperature immediately after production B. After aging at 250°C for 48 hours C. Measured at 150°C immediately after production D .Measurement table at room temperature after recycling test Sample symbol Melt flow value Calculated value of heat treatment minimum temperature (℃) Heat treatment temperature (6) Strength a (Kg b C-1 C-2 C-3 D-1 D-2 E- 1 E-2 F-1 F-2 G-1 〃 〃 〃 〃 〃 〃 〃 〃 〃 〃 -1) -I.O- 8.1 8.3 7,5 7.6 7.3 7.4 7 .4 7.5 7.1 - Todoroki 8.8 8,9 8.4 8.3 8.4 8.5 8.1 8.3 7.9 Strength/elongation measurement conditions A, b d are as follows: Tables *゛-F and -G) were polymerized.

(2) Melt molding In the same manner as (2) of Example 1, width 2801TIn1.
Films C, D, E, F and G each having a thickness of 50 μm were obtained.

(3) Each film C-G was subjected to tension heat treatment for 30 seconds at various temperatures using a tenter type heat treatment machine, and the films C-1 to C-
2, D-1, D-2, E-1, E-2, F-1, F-2
and G-1 were obtained.

Table 2 shows the evaluation results and recycling test results for the obtained film. Table 2 clarifies the importance of the lower limit temperature of constant length heat treatment in the method of the present invention.

In other words, the film heat-treated below the lower limit temperature is
It has low toughness at low temperatures and is not suitable for practical use. Elongation - 1 degree (5) C Low temperature toughness (5) Gel increase rate due to recycling (5) Note 81] 7,2 5.0 4.8 1:. :1 7.8 6.7 2.4 2.2 Comparative example of the present invention Measured at the same temperature and under the same measurement conditions.

Example 3 (1) Polymerization of PPS, Precure In the same manner as in (1)A of Example 1, melt flow 300
, T: 886°C, Tm: 284°C.

The obtained polymer was heated to 250°C in a hot air oven to perform precuring, and the melt flow after precuring was 5 ~
250 PPS 4 types (PPS-H, -1, -J and -
K) was obtained.

(2) Melt molding In the same manner as in (2) of Example 1, the thickness was 5
Films (H, I, J, K) of 0 μm were obtained.

(3) Heat treatment The films obtained in (3) above were heat treated for a fixed length at 270°C for 40 seconds using a tenter set heat treatment machine.
I-1, J-1, and K-1 were obtained.

Table 3 shows the evaluation results and recycling test results for the obtained film. Table 3 shows that the film produced by the method of the present invention using [high polymerization degree PPS] made by the method of increasing the polymerization degree by pre-curing after polymerization as a raw material also has less gel formation and can be used at low temperatures. It also shows that it has excellent toughness.

Example 4 (1) Polymerization of PPS, precure In the same manner as in Example 1 (1), melt flow was 1300.
and got 2000 PPS.

The PPS obtained in (1) above and the PPS polymerized in Example 3 (1) were heated to 250°C in a hot air oven and precured until the melt flow of both was 90%.
L, -M, and -N were obtained.

(2) Melt-molded brake cured polymer (2) of Example 1
) was melt-molded and formed into a 50 μm thick film (
L, M and N).

(3) Heat treatment The obtained films were heat treated for a fixed length in the same manner as in (3) of Example 3 to obtain films L-1, M-1, and N1.

Table 4 shows the evaluation results and recycling test results for the films L-1, M-1, and N-1.

Claims (1)

[Scope of Claims] 1. A thermoplastic resin composition mainly composed of highly polymerized polyphenylene sulfide with a melt flow value M of 10≦M≦130 is melt-sealed, extruded through a slit-shaped die, cooled and solidified to form a film. A method for producing a polyphenylene sulfide film, which is then subjected to a fixed length heat treatment for 1 second to 100 seconds at a temperature of 275° C. or lower and a lower limit temperature T_0 or higher determined by the following formula. T_0=1.3M+100