JPH0412746B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a polyphenylene sulfide film with improved weather resistance. [Prior art] Polyphenylene sulfide is a thermoplastic crystalline polymer with excellent heat resistance, electrical insulation, chemical resistance, and flame retardancy, and is mainly used as an engineering resin for injection molding materials. However, among polyphenylene sulfides, those with particularly high molecular weights are expected to be used as materials for films, fibers, and molding. [Disadvantages of the prior art] However, conventional polyphenylene sulfide has rather poor UV stability, that is, weather resistance, and its range of application is limited, severely limiting its use as a film that is often used outdoors. was. When a polyphenylene sulfide film is exposed outdoors, its mechanical strength significantly decreases in a fairly short period of time, and at the same time, the coloring increases to dark brown and transparency deteriorates significantly. The purpose of the present invention is to eliminate the above-mentioned drawbacks of conventional polyphenylene sulfide films, and to provide a polyphenylene sulfide film that suppresses deterioration of mechanical properties and increase in coloring to dark brown due to ultraviolet deterioration. That is, the object of the present invention is to provide a polyphenylene sulfide film having excellent weather resistance. The object of the present invention is the general formula

0.01 to 10 parts by weight of a compound having a molecular weight of 360 or more and having at least one bent triazole group in the molecule to 100 parts by weight of polyphenylene sulfide whose main component is the structural unit represented by [Formula] Contains and substantially has a density of
This is achieved with polyphenylene sulfide film that is 1.330-1.390 g/cc. Polyphenylene sulfide (hereinafter abbreviated as PPS) in the present invention has the general formula

The main component is a structural unit represented by the formula. The term "main component" means that the above-mentioned repeating unit is contained in an amount of 90 mol% or more, preferably 95 mol% or more.

[Formula] If the structural unit is less than 90 mol%, the crystallinity of the polymer will be insufficient, resulting in a decrease in heat distortion temperature, etc., making it difficult to obtain an excellent film. The remaining structural units may be random copolymerizable units, such as meta-bonds.

[Formula] Ether bond

[Formula] Sulfone bond

[Formula] Biphenyl linkage If

[Formula] Naphthyl bond

[Formula] Substituted phenyl sulfur id join

[Formula] Here, R represents a substituent such as alkyl, nitrophenyl, alkoxy group, etc.), trifunctional phenyl sulfide bond

Examples include [Formula]. In addition, the apparent melt viscosity of the polymer is
℃, shear rate 200 (sec) ^-1 under conditions of 50-100000
poise, preferably in the range of 70 to 50,000 poise. The compound having a benzotriazole group used in the present invention needs to have at least one benzotriazole group in its molecule and have a molecular weight of 360 or more. The benzotriazole group has the chemical formula

[Method of measuring characteristics, evaluation criteria]

In addition, the measuring method and evaluation criteria of the characteristics in the present invention are as follows. (1) Apparent melt viscosity When a molten polymer is extruded at temperature T and pressure P using a Koka type flow tester with a capillary die of length L and radius R, the volumetric discharge rate is Q. Then, the shear stress τ, apparent shear rate γ〓, and apparent viscosity μ are defined as follows. τ = (RP) / (2L) γ = (4Q) / (πR ² ) μ = τ / γ At this time, the curve μ = f obtained by plotting μ at that time for various γ = (γ〓), γ〓=
The value μ ₀ at 200 (sec) ^-1 was taken as an index of the melt viscosity of the polymer. However, in the present invention, L
The values measured at T=300° C. using a die with =10 mm and R=0.5 mm were used. (2) Tensile strength and elongation Measured using an Instron type tensile tester according to the method specified in JIS Z-1702. (3) Ultraviolet stability (weather resistance) The PPS composition is formed into a film with a thickness of approximately 30 μm, heat-treated at 220°C for 1 minute, and used as a sample. The tensile strength and elongation of the sample are measured by the method described above and used as initial values. UV exposure is carried out using a carbon arc type weather meter, and the sample is taken out at predetermined exposure times, and the tensile strength and elongation of the exposed sample are measured using the method described above. It was used as an indicator. In addition, color changes are indicated on the exposed film for each exposure time.
The non-added sample and the added sample were compared and judged by visual judgment. (4) Measurement of ultraviolet absorption curve Using a Hitachi automatic spectrophotometer, the ultraviolet to visible light absorption to transmission curves of the weathering agent and the PPS film added thereto were measured. (5) Measurement of density Using a density gradient tube using LiBr aqueous solution,
Measured at 25°C. [Examples] The present invention will be described below based on Examples. Example 1 (1) Polymerization of PPS 32.6 kg of sodium sulfide in an autoclave
(250 mol, including 40 wt% crystallization water), 100 g of sodium hydroxide, 18.0 kg of sodium benzoate (125
mol) and 79.2 kg of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were charged, and the temperature was gradually raised to 205° C. while stirring, and distillate 7 containing 6.9 kg of water was removed. 37.5 kg (255 mol) of 1,4-dichlorobenzene (hereinafter abbreviated as DCB) and 20.0 kg of NMP were added to the residual mixture, and the mixture was heated at 250°C for 3 hours. The reaction product was washed 8 times with pure water made by ion exchange method and dried at 100℃ for 24 hours using a vacuum dryer to obtain an apparent melt viscosity of 4000 Poise at 300℃ and 200 (sec) ^-1 , Tg90. ℃, 23Kg of PPS with Tm of 280℃ was obtained. (2) Preparation of composition To the PPS powder obtained in (1) above, Using a super mixer, we added and mixed the following weathering agent (the amount added was 0.01 to 10% of the total weight), and prepared 10 types of composition No. (including those without adding weathering agent). .1 to No.10) were obtained. (3) Preparation of film The composition obtained in (2) above was applied to two films each having a diameter of 30 mm.
The pellets are fed to a shaft extruder and pelletized, the pellets are fed to a 30 mm diameter single shaft extruder, melted at 310°C, extruded through a T-die with a linear lip of 200 mm in length and a gap of 1.0 mm, and the surface temperature is reduced to 20°C. It is electrostatically cast onto a metal drum kept at a constant temperature, cooled and solidified, and has a width of 150 mm and a thickness of 400 μm.
I got a sheet of Further, the sheet was stretched vertically at 95°C using a film stretcher (manufactured by Long, TM, USA).
Simultaneous biaxial stretching 3.5 times in each width, followed by constant length heat treatment at 220°C for 1 minute using a hot air oven to obtain film samples with a thickness of 30 μm (film No. 1~
No.10) was obtained. Films Nos. 1 to 10 in Table 1 all had densities in the range of 1.355 to 1.359 g/cc. In addition, a film similar to film No. 5 was heated at 270°C.
A film with a density of 1.395 g/cc that was heat-treated for a period of time had an initial strength of 13 Kg/mm ² and an elongation of 60%, but after 60 hours of irradiation, the elongation retention had decreased to 30%. (4) Evaluation Table 1 shows the evaluation results of the film sample obtained in (3) above. Table 1 shows that the object of the present invention can be achieved only when the content of the specific weathering agent is equal to or higher than the specific value referred to in the present invention. Example 2 (1) Polymerization of PPS Powdered PPS was obtained in the same manner as in Example 1 (1). (2) Preparation of compositions 3.5wt% of a compound having a benzotriazole group (weather resistant agent) having a different molecular weight was mixed with the PPS powder obtained in (1) above using a super mixer, and 5 types of compositions were prepared. I got it. (3) Preparation of film Extrusion, casting, stretching, and heat treatment were performed in the same manner as in (3) of Example 1 to obtain film samples (film Nos. 11 to 15) with a thickness of 30 μm. (4) Evaluation Table 2 shows the evaluation results of the obtained film samples. Table 2 shows that the object of the present invention can be achieved only when the molecular weight of the weathering agent having at least one benzotriazole group is equal to or higher than a specific value as referred to in the present invention.

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Claims (1)

[Claims] 1. Polyphenylene sulfide 100 whose main component is a structural unit represented by the general formula [Formula]
Contains 0.01 to 10 parts by weight of a compound having a molecular weight of 360 or more and having at least one benzotriazole group in the molecule, and has a substantially density of 1.330 to 1.390 g/cc. A polyphenylene sulfide film characterized by: