JPH07216087A - Light-resistant aromatic polysulfone-based polymer - Google Patents

Abstract

PURPOSE:To obtain the subject polymer containing sulfone linkage, ether linkage and isopropylidene linkage in its molecular chain and made up of isopropylidenetetrabromobiphenyl group structural unit and biphenyl group structural unit, etc., low in discolorability due to ultraviolet radiation. CONSTITUTION:This polymer contains sulfone linkage, ether linkage and isopropylidene linkage in the molecular chain and is made up of 4,4'- isopropylidenetetrabromobiphenyl group structural unit of formula I and biphenyl group structural unit of formula II and/or phenyl group structural unit of formula III.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-resistant aromatic polysulfone-based polymer having a low UV coloring property.

[0002]

2. Description of the Related Art Aromatic polysulfone-based polymers having a sulfone group in the molecular skeleton such as polysulfone, polyarylsulfone and polyarylethersulfone have excellent transparency, heat resistance and steam resistance.
It is a polymeric material that exhibits dimensional stability, is tough and has excellent mechanical strength over a wide temperature range. Conventionally, by utilizing this characteristic, it has been used for electric / electronic parts, automobile parts, medical equipment, industrial products, etc., and the production amount has expanded. However, conventional aromatic polysulfone-based polymers are colored in a light yellow color, and when the molded product is exposed to ultraviolet rays, the color changes from a light yellow color to a brown color, resulting in a decrease in transparency and a decrease in mechanical strength. There was a limitation that it could not be used for visual equipment or transparent objects used outdoors. Therefore, its usage is for transparent articles for indoor use such as coffee pots that do not matter much in colorability, or for non-transparent parts to which pigments and additives have been added in advance and for parts that are not exposed to direct sunlight. It was limited. Conventionally, in order to prevent the aromatic polysulfone-based polymer having a sulfone group from being colored by ultraviolet rays, there have been attempts to improve by kneading an ultraviolet absorber into the aromatic polysulfone-based polymer, Since the dispersibility of the ultraviolet absorber is poor and the effect of preventing coloration is poor, the problem has not yet been solved.

On the other hand, as a method for improving the light resistance of an aromatic polysulfone-based polymer having a sulfone group, for example, JP-A-4-222870 discloses polyvinyl alcohol, polyvinyl acetate, polyvinyl containing an ultraviolet absorber. Aromatic polyether sulfones coated with film-forming polymers such as pyrrolidone, polyacrylates are disclosed. Further, a method of coating the surface of an aromatic polysulfone polymer with a silicone resin hard coating agent having excellent surface hardness, scratch resistance and light resistance is also well known. However, even in these methods, satisfactory improvement in light resistance was not observed, and the adhesion was insufficient, and there was a problem that pretreatment with a primer, which causes a cost increase, was required. .

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a light-resistant aromatic polysulfone-based polymer having a main chain skeleton in which a radical blocking agent is incorporated and which has little ultraviolet coloring property.

[0005]

Means for Solving the Problems- (Phenyl group) -X-
A polymer comprising a repeating structural unit of (phenyl group)-(wherein X represents a bonding group connecting the phenyl groups) is X
It is known that the UV resistance and the radiation resistance vary depending on the type. In the aromatic polysulfone-based polymer according to the present invention, X is a sulfone group, an ether group and an isopropylidene group, and the order of bonds that are easily cleaved by ultraviolet rays is phenyl group-sulfone group bond>
Phenyl group-ether group bond> phenyl group-isopropylidene group bond> phenyl group-phenyl group bond. The cleavage of the main chain of the aromatic sulfone-based polymer with ultraviolet rays is linked to the formation of a chromophore that causes coloring through the generation of radicals, as described later. Therefore, as a method for preventing the coloring by ultraviolet rays, (1) the breaking of the polymer main chain by ultraviolet rays can be prevented, and (2) the breaking of the polymer main chain cannot be prevented, but radicals generated by the cutting can be generated early. There are two possible methods of blocking the formation of the chromophore, which will be described later, so that the formation of the chromophore described later will not occur. Of these, the method (1) is difficult because it changes the properties peculiar to the bond structure. Therefore, as a result of diligent studies on the method (2), the present inventors have found that even if the main chain of the polymer is cleaved by ultraviolet rays or the like, the generated phenyl radicals and phenoxy radicals are blocked early so that the chromophore The present inventors have found that it is possible to obtain an aromatic polysulfone-based polymer having good light resistance by incorporating a radical sequestering agent capable of suppressing the generation into the polymer main chain skeleton, and have reached the present invention.

That is, the present invention relates to an aromatic polysulfone polymer having a sulfone bond, an ether bond and an isopropylidene bond in its molecular chain, which is represented by the above formula (I). Achieved by providing a light-resistant aromatic polysulfone-based polymer containing a biphenyl group structural unit and a biphenyl group structural unit represented by the above formula (II) and / or a phenyl group structural unit represented by the above formula (III) it can.

The present invention will be described in detail below. In the present invention, the chromophore formed as a substance causing coloring of the aromatic polysulfone-based polymer is a polyenyl type cross-link formed from a phenoxy radical and a phenyl radical formed by the reaction formula shown in the following formula (IV). It is presumed to be a thing.

[0008]

[Chemical 4] (However, in the formula, Ph represents a phenyl group.)

By the way, it is a well known fact that an aromatic compound having a carbonyl group formed from a phenyl ring is extremely likely to develop color as shown by a quinone compound. Therefore, from this, it is reasonable to consider that the polyenyl-type crosslinked product formed by the reaction formula shown in the above formula (IV) is a chromophore.

As described above, the present invention aims to prevent the formation of this chromophore by incorporating a radical blocking agent into the main chain skeleton of the aromatic polysulfone polymer. The method for preventing the formation will be described in more detail. The following formula (V) formed by the main chain scission of an aromatic polysulfone polymer is described.

[0011]

[Chemical 5]

The radical of the oxygen portion of the phenoxy radical represented by the formula (VI), which is the first cause of coloration, is obtained by early blocking.

[0013]

[Chemical 6]

The following formula (VII) which prevents the structure formation of the phenoxy radical represented by and then causes hydrogen abstraction from this phenoxy radical

[0015]

[Chemical 7]

By blocking the phenyl radical represented by, it is possible to prevent the formation of a polyenyl type crosslinked product which is considered to be the chromophore.

There are various possible radical blocking agents, but those satisfying the purpose of the present invention are those in which the bond dissociation of --Cl or --OH bonded to the phenyl group remaining at the molecular end of the aromatic polysulfone polymer. Since it is preferably lower than the energy, the bond dissociation energy is 70 to 86.
kcal / mol, preferably 70-80 kcal / m
In order to prevent the risk of bleed-out, the compound must be a compound that can be incorporated into the main chain skeleton of the aromatic polysulfone polymer. That is, as the radical blocking agent used in the present invention, a biphenol derivative having a substituent having the above-mentioned radical blocking action and having a bond dissociation energy within the above range, or a diphenol derivative such as bisphenol A. Alternatively, a monophenol derivative may be used. More specifically, the bond dissociation energy is 80 kc.
It is a diphenol compound containing al / mol of bromine, or a phenol compound, and these compounds can be incorporated into the main chain or at the main chain terminal as one component of the aromatic polysulfone polymer according to the present invention. In the present invention, in consideration of its easy availability, the compound to be incorporated into the main chain of the aromatic polysulfone polymer is 4,
As the compound incorporating 4'-isopropylidene tetrabromobiphenol, that is, tetrabromobisphenol A (hereinafter referred to as "tetrabromobisphenol A") at the main chain terminal of the polymer, 2,4
The most preferable example is 6-tribromophenol (hereinafter, simply referred to as "tribromophenol"). In the present invention, by incorporating tetrabromobisphenol A in the main chain of the aromatic polysulfone polymer, the radical blocking agent is always present near the main chain cleavage site of the polymer by ultraviolet light, The efficiency of radical sequestration is extremely high.

In the present invention, when a compound having a substituent having a bond dissociation energy of more than 86 kcal / mol is used as the radical blocking agent, it remains at the molecular end of the aromatic polysulfone polymer. Cl and -OH (bond dissociation energy is 8
6 kcal / mol and 85 kcal / mol) dissociated radicals cannot be blocked and 70 kcal / m
When a compound having a substituent having a bond dissociation energy lower than that of ol is used, it decomposes even with visible light energy at one time, and there is a problem that the radical blocking action cannot be sustained for a long time because it is too unstable. Therefore, it is not preferable to incorporate these radical blocking agents into the main chain skeleton of the aromatic polysulfone polymer.

By the way, the aromatic polysulfone polymer of the present invention which can prevent the formation of the chromophore by incorporating the radical blocking agent into the main chain skeleton is represented by the following general formula (VIII):

[0020]

[Chemical 8]

(However, y = 0 to 1 and z = 0 to 1,
And y + z = 1. 2) a repeating structural unit, that is, a polymer containing a dichlorodiphenyl sulfone component and a biphenol component and / or a phenol component in the molecular chain. Therefore, in the present invention, it is important that the molecular chain contains a biphenyl group structural unit represented by the above formula (II) and / or a phenyl group structural unit represented by the above formula (III).

In order to increase the heat resistance of the aromatic polysulfone polymer of the present invention, the above-mentioned general formula (VIII)
In the case of z = 1, that is, only the biphenyl group is preferable, but in this case, the solubility in the polymerization solvent is poor during the polymerization synthesis of the aromatic polysulfone polymer, and the degree of polymerization is increased, such as precipitation. Therefore, the properties as a polymer cannot be obtained. Therefore, the aromatic polysulfone-based polymer of the present invention is preferably a mixed system of a biphenol component and a phenol component, which is soluble in a polymerization solvent and has a high glass transition point (Tg), In the general formula (VIII), it is particularly preferable that z / y = 0.5 / 0.5.

Further, in the present invention, as described above, tetrabromo as a radical blocking agent is added to the main chain skeleton of the aromatic polysulfone polymer having the repeating structural unit represented by the general formula (VIII). By incorporating bisphenol A, the biphenyl group structural unit or a part of the phenyl group structural unit is replaced with the 4,4'-isopropylidenetetrabromobiphenyl group structural unit represented by the above formula (I). Therefore, the light-resistant aromatic polysulfone-based polymer of the present invention has the following general formula (IX)

[0024]

[Chemical 9]

(However, y and z are the same as those in the general formula (VIII).) A polymer composed of repeating structural units.

As the aromatic polysulfone polymer to which the present invention is applied, those having a repeating structural unit represented by the general formula (VIII) have been mentioned above, but the present invention is not limited thereto. Without the following general formula (X)

[0027]

[Chemical 10]

An aromatic polysulfone polymer having a repeating structural unit represented by the following can also achieve the object of the present invention by replacing a part of bisphenol A with tetrabromobisphenol A.

Therefore, the aromatic polysulfone-based polymer which is the object of the present invention and which can prevent the formation of the chromophore by incorporating the radical blocking agent into the main chain skeleton is
As mentioned above, the following general formula (XI)

[0030]

[Chemical 11]

(However, X represents a sulfone group, an ether group or an isopropylidene group, and these bonding groups may be arranged alternately or may be arranged randomly.) A polymer composed of structural units, that is, an aromatic polysulfone-based polymer having a sulfone bond, an ether bond and an isopropylidene bond in the molecular chain is preferable.

In the present invention, the 4,4'-isopropylidenetetrabromobiphenyl group structural unit formed by incorporating tetrabromobisphenol A into the main chain of the aromatic polysulfone polymer is an aromatic polysulfone polymer. It is desirable that the polymer contains 0.4 to 5.0 mol%, preferably 1.6 to 3.0 mol%. 4,
When the content of the 4'-isopropylidenetetrabromobiphenyl group structural unit is less than the above range, the aromatic polysulfone polymer main chain is cleaved by ultraviolet rays as shown in the reaction formula (IV). The phenyl radical or phenoxy radical generated by the above is not sufficiently incorporated into the polymer main chain skeleton of the radical blocking agent that can suppress the formation of the chromophore at an early stage, and therefore, an aromatic polysulfone system having excellent light resistance It is not preferable because a polymer cannot be obtained. When the content of the 4,4′-isopropylidenetetrabromobiphenyl group structural unit exceeds the above range, the condensation reactivity decreases during the production of the light-resistant aromatic polysulfone polymer of the present invention, There is a drawback that the degree of polymerization is difficult to increase. In the present invention,
As described above, in order not to leave reactive —Cl or —OH at the molecular chain end of the aromatic polysulfone polymer, and to further enhance the light resistance effect of the aromatic polysulfone polymer, It is desirable to replace the molecular end of the aromatic polysulfone polymer with a 2,4,6-tribromophenyl group.

Next, in the present invention, a radical blocking agent is incorporated in the main chain skeleton, and an aromatic polysulfone polymer excellent in light resistance can be produced by a known method. Specifically, for example, in the presence of an alkali metal compound such as deoxidized sodium carbonate or potassium carbonate, in an organic polar solvent such as N-methyl-2-pyrrolidone or dimethylacetamide, dichlorodiphenylsulfone or difluorodiphenyl is used. Produced by blending a dihalogenodiphenyl compound such as sulfone, a dihydric phenol compound such as hydroquinone, and tetrabromobisphenol A and / or tribromophenol as a radical blocking agent at a predetermined molar ratio and subjecting them to polycondensation reaction. You can do it. At this time, the amount of tetrabromobisphenol A added is adjusted so that the content of the 4,4′-isopropylidenetetrabromobiphenyl group structural unit in the obtained aromatic polysulfone-based polymer falls within the above-mentioned desirable range. It is desirable that the amount is 0.008 to 0.050 mol, preferably 0.016 to 0.030 mol, per mol of the dihalogenodiphenyl compound as a monomer.
Tribromphenol is preferably added as a viscosity modifier at the end of the polymerization of the aromatic polysulfone polymer to terminate the polymerization. It is desirable that the amount of addition be such that the residual-Cl amount obtained in advance from the quantitative determination of the end groups of the aromatic polysulfone polymer obtained can be sufficiently replaced.

The light-resistant aromatic polysulfone-based polymer of the present invention has been described above. In the method of simply kneading the conventionally known ultraviolet absorber as described above, the ultraviolet absorber which is a low molecular weight compound is used. The high molecular weight polymer is not molecularly mixed, and the negative effects such as deposition on the surface with time are combined, and the coloring property is low, and the light-resistant aromatic polysulfone polymer that does not change with time is inevitable. I couldn't get it. As in the present invention, by incorporating a radical sequestering agent into the main chain skeleton of the polymer, the phenoxy radical or phenyl radical, which is the root cause of coloring, can be effectively sequestered early and before the formation of the chromophore. It was possible for the first time to stay.

[0035]

The present invention will be described in more detail below with reference to Examples and Comparative Examples, but these do not limit the present invention in any way.

In the following examples and comparative examples, dichlorodiphenyl sulfone (hereinafter abbreviated as "DCDPS") or difluorodiphenyl sulfone (hereinafter abbreviated as "DFDPS") which is a raw material monomer, hydroquinone (hereinafter abbreviated as "HQ"), Biphenyl (hereinafter "B")
And tetrabromobisphenol A (hereinafter abbreviated as “TBA”) have a molar ratio represented by the following mathematical formula 1. In addition, in the present example and the comparative example, as the raw material monomers, high purity products were used.

[0037]

[Equation 1]

Here, the molar ratio X of TBA is 0, 0.0.
There are four types, 08, 0.016 and 0.032. When X = 0 and 0.008, DCDPS is used, and when X = 0.016 and 0.032, when the content of TBA in the aromatic polysulfone polymer is high, the reactivity is reduced. High DFDPS was used. Table 1 shows the molar ratio of each raw material monomer.

Example 1 (Purification of Polymerization Solvent) Dimethylacetamide (hereinafter referred to as "DM"
(Abbreviated as “Ac”) 500 g of special grade reagent to 500 g of desiccant CaH ₂
g was added, and the mixture was stirred overnight with a stirrer. After vacuum distillation,
5 parts of molecular sieves (vacuum dried at 220 ° C. or higher for 7 hours, cooled, and then replaced with nitrogen) were put therein, bubbled with nitrogen, sealed, and stored at room temperature.

(Synthesis of Polymer) An aromatic polysulfone polymer in which TBA was incorporated in the molecular skeleton at a molar ratio X of the TBA of 0.008 was synthesized by the following method.
17.23 g (0.060 mol) of DCDPS as a raw material,
3.27 g (0.0297 mol) of HQ and 5.54 of B
g (0.0297 mol) and TBA 0.26 g
After measuring (0.000475 mol), DM as a polymerization solvent
It was dissolved in 150 ml of Ac and transferred to a separating funnel. To the separating funnel, 14 ml of azeotropic toluene was added in order to remove water generated in the reaction system during the polymerization. Then, a separable flask for polymerization (internal volume: 500
ml) on a heatable magnetic stirrer,
Insert a large stirrer chip, and then add 8.29 g (0.06 mol) of high-purity potassium carbonate for neutralization,
The atmosphere was replaced with nitrogen. Then, a separating funnel containing the monomer solution and a condenser with a water receiver were placed on a separable flask. The monomer solution in the separatory funnel was added dropwise while flowing the nitrogen while rotating the stirrer, and after the completion, the heater was heated to raise the polymerization temperature to 160 ° C. The polymerization time was 6 hours. During the polymerization, the produced water in the reaction system was azeotropically distilled with toluene, and was removed from the water receiver condenser. After the polymerization is completed, the polymerization solution is cooled and then distilled and purified.
150 ml of c was added to reduce the viscosity, and the polymerization liquid was filtered under reduced pressure with a G4 glass filter. The filtrate was gradually poured into methanol to precipitate a polymer. Purification of the precipitate is carried out by washing the methanol precipitate with distilled water, removing water, vacuum drying, dissolving again in 150 ml of distilled and purified DMAc, reprecipitating with methanol, washing with water, removing water and vacuum drying. Carried out. The obtained aromatic polysulfone polymer purified product was 13 g.

(Measurement of Viscosity of Polymer) 0.5 g of the purified polymer was dissolved in 100 ml of N-methylpyrrolidone, and the viscosity was measured at 30 ° C. using an Ubbelohde viscometer. The viscosity measurement results (η _SP / C) of the polymer are shown in Table 2.

(Measurement of UV resistance of polymer) The UV coloring resistance of the purified aromatic polysulfone polymer having TBA incorporated in the main chain skeleton was examined by the change in yellowness (YI value). The test film was prepared by preparing a methylene dichloride solution having a concentration of 5% by weight, casting this solution on a glass plate with a doctor knife, and then vacuum drying (holding at 60 ° C. for 12 hours). The thickness of the film after drying was 16 to 17 μm. For irradiation with ultraviolet rays, a high pressure mercury lamp (400 W) manufactured by Wako Electric Co., Ltd. was used as a light source. And irradiation area 35 × 35m
A sample for measurement was prepared by sticking a film on a cardboard with a window of m opened, and the distance between the light source and the sample was 30 cm, and the sample was irradiated with ultraviolet rays for a predetermined time. The yellowness (YI value) was measured by using an SM color computer (SM-3) manufactured by Suga Test Instruments Co., Ltd. After measuring the YI value, irradiation / measurement was performed again on the same sample. The wavelengths contained in the high-pressure mercury lamp used are as shown in Table 3.

Examples 2 and 3 The use of DFDPS instead of the starting DCDPS,
And so that the molar ratio of each raw material becomes the value shown in Table 1,
The amount of each raw material charged was DCDPS 17.23 g (0.06
0 mol), HQ 3.27 g (0.0297 mol), B
5.54 g (0.0297 mol) and TBA 0.26
g (0.000475 mol), in Example 2, DFDPS was 15.254 g (0.060 mol),
3.251 g (0.0295 mol) of HQ and 5.4 of B
97 g (0.0295 mol) and TBA 0.522
g (0.00094 mol), and in Example 3, 15.254 g (0.060 mol) of DFDPS, H
3.198 g (0.0290 mol) of Q and 5.40 of B
8 g (0.0290 mol) and 1.044 g of TBA
Purification of the polymerization solvent, synthesis of the polymer, viscosity measurement of the polymer and ultraviolet resistance measurement of the polymer were carried out in the same manner as in Example 1 except that the amount was (0.0019 mol). The amount of the obtained purified product of polymerization was 6.53 g in Example 2.
And in Example 3, it was 5.71 g. Further, the viscosity measurement result of the obtained polymerized product and the wavelength contained in the high-pressure mercury lamp used for the ultraviolet resistance measurement were as shown in Table 2 and Table 3, respectively.

Comparative Example 1 The amount of each raw material charged was such that TBA was not incorporated in the main chain skeleton of the aromatic polysulfone polymer, that is, the molar ratio of each raw material was the value shown in Table 1. DCDPS
17.23 g (0.060 mol), HQ 3.27 g
(0.0297 mol), B 5.54 g (0.0297 mol) and TBA 0.26 g (0.000475 mol)
In the same manner as in Example 1 except that DCDPS was 17.23 g (0.060 mol), HQ was 3.30 g (0.030 mol) and B was 5.59 g (0.030 mol). Then, the polymerization solvent was purified, the polymer was synthesized, the viscosity of the polymer was measured, and the ultraviolet resistance of the polymer was measured. The amount of the purified product obtained by the polymerization was 15 g. Also,
The wavelengths contained in the high-pressure mercury lamp used for the viscosity measurement results and the ultraviolet resistance measurement of the obtained purified product of polymerization were as shown in Table 2 and Table 3, respectively.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

The YI value before ultraviolet irradiation of the films of Examples 1 to 3 and Comparative Example 1 containing TBA in the respective molar ratios shown in Table 1 was 2. The YI value after irradiating the samples of each Example and Comparative Example with ultraviolet rays for a predetermined time was measured, and the residue obtained by subtracting the YI value before irradiation was determined as the change in yellowness (ΔYI). FIG. 1 shows the relationship between the UV irradiation time and the TBA content, which affects ΔYI, of the samples of Examples 1 to 3 and Comparative Example, based on the measurement results. As shown in FIG. 1, it is clear that the incorporation of TBA into the molecular skeleton drastically reduces the coloring property by ultraviolet rays. As is clear from FIG. 1, the polymer according to the present invention can provide a transparent aromatic polysulfone polymer having excellent light resistance.

[0049]

EFFECTS OF THE INVENTION The aromatic polysulfone-based polymer in which a specific radical blocking agent is incorporated in the main chain skeleton of the present invention is a mere kneading of an ultraviolet absorber or a surface coating treatment with a resin having light resistance. Compared with the conventionally known aromatic polysulfone-based polymer, which did not always show a sufficiently satisfactory improvement in terms of light resistance, the ultraviolet coloring property was low,
It has excellent light resistance and can be used for visual equipment and transparent objects used outdoors. Further, since there is no fear of bleeding out, the light resistance effect lasts for a long time, which is also an advantage that cannot be obtained by the above conventional method.

[Brief description of drawings]

1] Ultraviolet (UV) irradiation time and TBA affecting the yellowness change (ΔYI) of an aromatic polysulfone polymer.
It is a graph which shows the relationship with content (mol fraction). Figure 1
, The horizontal axis (TBA mol fraction) and the vertical axis (ΔY
I) is shown on a uniform scale.

Claims (1)

[Claims] 1. An aromatic polysulfone-based polymer having a sulfone bond, an ether bond and an isopropylidene bond in its molecular chain, represented by the following formula (I): 4,4'-isopropylidene tetrabromobiphenyl group structural unit represented by the following formula (II) A biphenyl group structural unit represented by and / or the following formula (III): A light-resistant aromatic polysulfone-based polymer containing a phenyl group structural unit represented by: