JP3037974B2 - Polyamide composition having excellent nitrogen oxide resistance - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a synthetic polyamide white composition obtained by imparting high nitrogen oxide resistance (NOx resistance) to a synthetic polyamide widely used as a fiber or a resin.

(Prior art)

In general, synthetic polymers, particularly synthetic polyamide fibers or resins, contain a yellow-brown impurity as a substrate and therefore have a large absorption in the visible short-wavelength region (purple-blue), and therefore have insufficient violet-blue reflection. Visible in One of the ways to replenish the purple-blue color that was lacking to make it look whiter is to use a blue-blue dye to add a blue tint (so-called bluing). This appears to be white at first glance, but the brightness has actually decreased. You're just looking at a bluish tint (with reduced reflectivity).

Therefore, in order to obtain a pure white product, it is essential to use a fluorescent whitening agent as another method for replenishing the insufficient visible short wavelength region. The fluorescent brightener absorbs invisible ultraviolet light, shifts its energy to longer wavelengths and emits fluorescent light in the visible short wavelength region. Things.

Bis-triazinylamino-stilbene-based, bis-triazolyl-stilbene-based and bis-styryl-diphenyl-based fluorescent whitening agents have been used in the past.

[Problems to be solved by the invention]

All of the optical brighteners that can be applied to the synthetic polyamide compositions that have been conventionally commercially available have the effect of suppressing or preventing the deterioration and discoloration of the synthetic polyamide due to nitrogen oxides, that is, the nitrogen oxide resistance (so-called NOx resistance) is extremely low. In addition, the influence of NOx causes not only deterioration and loss of whiteness but also dirty coloring, that is, yellowing contamination.

Regarding NOx mainly emitted from automobiles and factories, etc., although emission standards are set by law, it continues to increase nationwide, and has developed into a major social problem.

By the way, synthetic polyamides, which are widely used as fibers and molded products, are susceptible to deterioration by NOx.
The use of synthetic polyamides, particularly their white product compositions, in areas where they are frequently exposed to extremes has been extremely limited.

If the synthetic polyamide has improved NOx resistance, its use will be greatly expanded, and there has been a strong demand from the industry for a synthetic polyamide white composition having excellent NOx resistance.

[Means for solving the problem]

The present inventors have conducted intensive studies to solve this problem, and as a result, the general formula (Wherein, R ₁ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogen atom or a sulfonic acid group or a salt thereof,
R ₂ and R ₃ are the same or different and each represent a hydrogen atom, a halogen atom or a sulfonic acid group or a salt thereof, and X represents a sulfonic acid group or a salt thereof, an alkylsulfonium salt, an arylsulfonyl group, a carboxyl group, an alkoxycarbonyl group, Aryloxycarbonyl group, cyano group (Where Y represents a sulfonic acid group or a salt thereof), a 2- (substituted styryl) -methyl group-substituted benzoxazole derivative represented by the following formula is added to the synthetic polyamide, and fluorescence is emitted to the visible short-wavelength region of the synthetic polyamide. When performing radiant reinforcement, it has been found that a white composition with very high NOx resistance is obtained. Here, in the above formula, examples of the salt of the sulfonic acid group include alkali metal salts such as sodium and potassium, amine salts, and quaternary ammonium salts.

The chemical structure of the 2- (substituted styryl) -methyl group-substituted benzoxazole derivative represented by the above general formula according to the present invention is characterized by the fact that benzoxazolyl- is used as a chromophore for enhancing the fluorescence emission to the visible short wavelength region. Using a styrene skeleton and a methyl group as a substituent on the benzene nucleus of the benzoxazole moiety to protect this chromophore from nitrogen oxide attack, this methyl group plays an important role in protecting the chromophore It is in.

The protective action of the chromophore from NOx by the methyl group is a unique phenomenon that has a prominent effect only on the benzoxazole-styrene skeleton and hardly exhibits a protective effect in other structures.

For example, a chromophore using a stilbene skeleton or an ethylene group, which is generally used and widely used for polyamide, has almost no effect on NOx resistance even if a methyl group is provided.

Therefore, it is considered that the interaction between the benzoxazolyl-styrene skeleton and the methyl group located only in the benzene nucleus of the benzoxazole moiety exerts excellent NOx resistance, and is obtained only when these two conditions are satisfied. It can be called a characteristic.

The 2- (substituted styryl) -methyl-substituted benzoxazole derivatives represented by the above general formula according to the present invention are the corresponding p-substituted cinnamic acids and the corresponding aminocresols in which the amino group and the hydroxyl group are in the o-position. And a sulfonic acid group-substituted benzoxazole derivative can be easily produced by dehydration-condensation by a generally known method, and a sulfonic acid group-substituted benzoxazole derivative can be produced by a generally known sulfonation method of reacting the corresponding benzoxazole derivative with fuming sulfuric acid, Alternatively, it can be easily produced by using an intermediate substituted with a sulfonic acid group. These 2- (substituted styryl) -methyl group-substituted benzoxazole derivatives are described in JP-B-40-6100, JP-B-40-26870, and JP-B-40-5870.
It is described in many patent publications such as Japanese Patent No. 259 and Japanese Patent Application Laid-Open No. 62-25174, and is well known.

For example, a condensation reaction of 29.5 g of 2,5-dichloro-4-methylsulfonylcinnamic acid and 12.9 g of cresamine together with 4 g of boric acid and 15 g of ethylene glycol in a nitrogen stream at 190 to 200 ° C. for 2.5 hours is carried out, and this is treated with dimethylformamide (DMF ) To give 2- (2,5-dichloro-4-) obtained by recrystallization.
26.8 g of methylsulfonyl-styryl) -5-methyl-benzoxazole was added to 100 g of 20% fuming sulfuric acid and stirred at 45 ° C. The end point of the reaction was monitored by TLC, and the reaction was completed in 1 hour. The reaction was drained into ice water containing salt,
Washed with saline and dried, containing 23.2 g of sodium chloride.
(2,5-dichloro-4-methylsulfonyl-styryl)
47.1 g of sodium sulfonate of -5-methyl-benzoxazole are obtained.

When a synthetic polyamide is treated using the 2- (substituted styryl) -methyl group-substituted benzoxazole derivative represented by the above general formula according to the present invention, all generally known treatment methods can be applied. It can be easily applied to any of ordinary dyeing, kneading into a resin body by kneading, and a method of coloring a stock solution.
The amount used is usually from 0.01% to 2% for dyeing, preferably from 0.05% to 1%, and from 0.005 PHR to 1 PHR, preferably from 0.01 PHR to 0.4 in resin kneading and soaking.
PHR range.

Hereinafter, the present invention will be described in more detail with reference to Examples and Reference Examples.

In addition, NOx resistance test is performed by nitric oxide gas exposure test based on JIS L0855, and judgment is made by measuring the fluorescence reflection of the test specimen before and after exposure treatment using a fluorescence spectrophotometer (RF-540 manufactured by Shimadzu Corporation) Then, a comparison value (relative value) and visual judgment (visual sensation) were performed with the value before exposure treatment as 100.

Example 1 Compound (1) of the present invention in a dye bath adjusted to pH 3.5 with 0.1% owf, bath ratio 1:20 and acetic acid at 90 ° C. using a nylon cloth at 6 ° C.
After dyeing for 0 minutes, the product was washed with water, soaped, washed with water and dried, and subjected to an exposure test.

For comparison, the same dyeing and exposure tests were carried out using the following compounds a and b instead of the compounds of the present invention for reference.

Example 2 0.02 PHR of compound (2) of the present invention and 0.4 PHR of titanium dioxide
Is kneaded with nylon-6 pellets at 220 ° C in a Labo Plastomill (Labo Plastomill: manufactured by Toyo Seiki).
The obtained melt was taken out, subjected to a hot press and a cooling press, and a white polyamide resin plate obtained was subjected to an exposure test.

For comparison, the following compounds c and d were used as reference examples instead of the compound of the present invention, and kneading and exposure tests were similarly performed.

Example 3 The compound (3) of the present invention was treated in the same manner as in Example 2 using the following compounds e and f as reference examples.

Example 4 The compound (4) of the present invention was stained in the same manner as in Example 1, and the following compound g was similarly treated as a reference example.

Example 5 The dyeing treatment was carried out using the compound (5) of the present invention in the same manner as in Example 1, and the results of the exposure test are shown.

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Claims (1)

(57) [Claims] (1) General formula (Wherein, R ₁ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogen atom or a sulfonic acid group or a salt thereof,
R ₂ and R ₃ are the same or different and each represent a hydrogen atom, a halogen atom or a sulfonic acid group or a salt thereof, and X represents a sulfonic acid group or a salt thereof, an alkylsulfonium salt, an arylsulfonyl group, a carboxyl group, an alkoxycarbonyl group, Aryloxycarbonyl group, cyano group, Or Wherein a 2- (substituted styryl) -methyl group-substituted benzoxazole derivative represented by (where Y represents a sulfonic acid group or a salt thereof) is blended with a synthetic polyamide; Composition.