CN101817947B - Wideband ultraviolet absorber for polyolefin and preparation method thereof - Google Patents

Abstract

The invention discloses a novel ultraviolet light absorber with good absorption effect in a wide ultraviolet wave range (200nm-420nm) and a preparation method thereof. The main components of the novel ultraviolet absorber include: phenyl salicylate and its derivatives, triazines or o-hydroxybenzotriazole compounds. The preparation method of the novel ultraviolet absorber is: phenyl salicylate or its derivatives are heated and pre-melted until the white crystals are all transformed into viscous liquids, and then benzotriazoles or triazines are added and heated at 150- Fully stir the reaction at 180°C until the two phases are completely melted into one phase. After cooling, the broadband ultraviolet light absorber can be obtained by grinding. The broadband ultraviolet absorber of the present invention can be widely used in the light protection of PVC, PS, PP and other polyolefin products which are easy to be degraded by photooxygen. When the polyolefin product containing the ultraviolet light absorber is used outdoors, the long-term retention rate of its comprehensive performance is greatly improved.

Description

Broad-band ultraviolet light absorber for polyolefin and preparation method thereof

technical field

The invention relates to the technical field of polymers, in particular to an ultraviolet absorber for polyolefin and a preparation method thereof.

technical background

Common UV absorbers for polyolefins, such as benzophenones, triazines, and benzotriazoles, all have a common feature, that is, they have intramolecular hydrogen bonds. The existence of this structure allows the compound to convert electron excitation energy into vibrational energy in a non-radiative way when the compound is irradiated by ultraviolet light and the electron spin multiplicity remains unchanged (S ₁ ～～～～～→ S ₀ ), so as to realize the protection of the matrix material.

Due to their different molecular structures, different types of ultraviolet light absorbers have specific and limited absorption bands and absorption capabilities for ultraviolet light, which leads to insufficient ultraviolet protection ability of a single ultraviolet light absorber for materials. For example: the commonly used 2-hydroxy-4-n-octyloxybenzophenone (UV531) has a narrow absorption width and only has good absorption for ultraviolet light waves of 250nm-330nm, and has almost no effect on ultraviolet light in other frequency bands , so the protection of the substrate is very limited. It is still an unsolved problem in this field to seek ultraviolet light absorbers with strong absorption effect in a wide ultraviolet range.

Reasonable compounding of photostabilizers with different structures is an effective way to improve photostabilization efficiency. For example: L.Avar et al. investigated the influence of hindered amine light stabilizers and UV absorbers mixed in a certain proportion on the UV aging behavior of polyacrylate coatings, and found that the combination of the two can more effectively delay the coating aging progress. T.Kurumada et al. found that after the hindered amine light stabilizer and UV absorber are compounded, the hindered amine light stabilizer is protected by the UV absorber in the early stage, reducing the loss of hindered amines, and the hindered amine is free radicals. The trapping ability in turn protects the UV absorber from free radical attack, with the overall result being enhanced photostabilization efficiency. The biggest problem in the compounding of such stabilizers with different photoprotection mechanisms is that the compatibility and matching of the performance and structure of the additives are difficult to be suitable, and there is often a problem of partial performance offsetting each other.

Compounding stabilizers with the same stabilization mechanism but different absorption bands has become a new focus of attention in the field. At present, there are not many research reports in this area. The only research report is found in Y. Dobashi et al. after compounding different structural UV absorbers (UVA-A and UVA-B) and found that the two have a certain synergistic enhancement effect.

Aiming at the deficiencies of the existing research, the present invention selects the ultraviolet light absorber as the compounding object, and according to the absorption peak characteristics of each ultraviolet light absorber, utilizes the compounding technology to obtain a broadband compound with a significant synergistic enhancement effect in the 290nm-420nm band. Ultraviolet light absorber, which not only overcomes the contradiction between the compatibility and matching of different stabilization mechanism additives, and the conflict between partial effects, but also improves the compatibility with the substrate, and can provide polyolefin materials with Better photoprotection.

Invention content:

The present invention proposes a polyolefin ultraviolet light absorber and its preparation method aimed at the deficiencies of the prior art, in order to solve the problem that the existing ultraviolet light absorber has limited absorption frequency band and intensity in the ultraviolet light region and cannot completely cover the ultraviolet light region The problem.

The concrete technical scheme that realizes the above-mentioned purpose of the present invention is as follows:

The broadband ultraviolet absorber for polyolefin mainly includes: 0.25-0.5 phr of phenyl salicylate compound or its derivatives, 0.5-0.75 phr of phenylacrylic acid compound or triazine compound. In the technical scheme of the above-mentioned broadband ultraviolet light absorber for polyolefin, the phenyl salicylate compound or its derivatives can be one kind of compound, or two or more kinds of compounds; The triazine compound or triazine compound can also be one compound, or two or more compounds.

In the above-mentioned technical scheme of broadband ultraviolet light absorber for polyolefins, phenyl salicylate compounds and derivatives thereof with the following structures are preferred:

Wherein R ₁ is one of H, -C(CH ₃ ) ₃ and -C ₈ H ₁₇ . For benzotriazole compounds, it is preferred to use those with the following structure:

Wherein R ₂ is Cl; R ₃ is

One of the structures. For triazine compounds, preferably select those with the following structure:

Wherein R ₄ , R ₅ and R ₆ are respectively

The above-mentioned broadband ultraviolet absorber for polyolefins is prepared by the following method: pre-melt the proportioned amount of phenyl salicylate compounds or derivatives thereof until the white crystals are all transformed into viscous liquids, and then add The benzotriazole compound or triazine compound is fully stirred and reacted at 150-180°C until the two phases are completely melted into one phase, and the broadband ultraviolet light absorber is obtained by grinding after cooling. During the stirring reaction process, UV absorbers with different structures interact physically and chemically to form a new composite UV stabilizer.

In the preparation method of the above-mentioned broadband ultraviolet absorber for polyolefins, the heating pre-melting temperature of the phenyl salicylate compound or its derivatives is generally in the range of 130°C to 150°C; After the oxazine compound, the stirring reaction temperature is controlled at 150-180°C, and the reaction time is generally 1-8 hours, the specific time is related to the temperature and the specific polymer; the stirring speed of the reaction is generally in the range of 50-300 rpm.

The experimental results show that the ultraviolet light absorber provided by the present invention effectively improves the absorption intensity and width of ultraviolet light, and the polyolefin material obtained by adding the novel ultraviolet light absorber provided by the present invention has a relative For polyolefin materials, the light stability performance has been significantly improved, and the long-term retention rate of mechanical properties has been greatly improved. The reasons for the above phenomenon are as follows:

UV absorbers with different structures have different absorption frequency bands and intensities for UV light. Through scientific and reasonable compounding, a new ultraviolet light absorber can be prepared, its absorption width in the ultraviolet region is significantly increased, the absorption intensity is also greatly improved, and the light protection ability of the base material is greatly improved. . See the examples for specific protective effects.

Description of drawings

Accompanying drawing 1 is the ultraviolet light absorption spectrogram of broadband ultraviolet light absorber I of the present invention and corresponding single ultraviolet light absorber o-hydroxysalicylate phenyl ester and triazine 5.

Accompanying drawing 2 is broadband ultraviolet light absorber IV of the present invention and corresponding single ultraviolet light absorber ortho-hydroxy salicylate phenyl ester and 2-(2-hydroxyl-3,5-dicumylphenyl)-phenylglycerine The UV absorption spectrum of azoles.

It can be clearly seen from Figure 1 that o-hydroxyphenyl salicylate has two absorption peaks at 230nm-250nm and 280nm-320nm, while triazine 5 has double absorption peaks at 330nm-380nm. The new broad-band UV absorber I prepared by the intercombination of the two exhibits stronger and broader absorption peaks in the range of 210nm to 390nm. Similarly, it can be clearly seen from Fig. 2 that the novel broadband ultraviolet light absorber IV is more o-hydroxy phenyl salicylate and 2-(2-hydroxyl-3,5-dicumylphenyl)-benzotriazole, which The width of the ultraviolet absorption peak increases, and the absorption intensity increases.

specific implementation

The following is a specific description of the present invention through examples. In the following examples, the parts of each component are parts by weight (phr).

Example 1:

Heat and melt 0.25phr o-hydroxyphenyl salicylate until all the white crystals turn into a viscous liquid, then add 0.75phr triazine 5 into the viscous liquid, stir and react at 180°C for about 4h, until two The ultraviolet light absorber is completely melted into one phase, and after cooling, it is ground to obtain the broadband ultraviolet light absorber I.

Example 2:

Preheat and melt 0.5phr p-octylphenyl salicylate until all the white crystals turn into viscous liquid, then add 0.5phr2-(2-hydroxy-3,5-dicumylphenyl)-benzo Add the triazole into the viscous liquid, stir and react at 160°C for about 3 hours, until the two types of UV absorbers are completely melted into one phase, and then grind after cooling to obtain the broadband UV absorber II.

Example 3:

Preheat and melt 0.4phr p-tert-butylphenyl salicylate until all the white crystals turn into viscous liquids, then add 0.6phr2-(2-hydroxyl-3-tert-butyl-5-methylphenyl )-5-Chlorobenzotriazole was added to the viscous liquid, stirred and reacted at 170°C for about 5 hours, until the two types of UV absorbers were completely melted into one phase, and then ground after cooling to obtain broadband UV Absorbent III.

Example 4

Preheat and melt 0.5phr o-hydroxyphenyl salicylate until all the white crystals turn into viscous liquid, then add 0.5phr2-(2-hydroxy-3,5-dicumylphenyl)-benzotriazole Add it into the viscous liquid, stir and react at 165°C for about 2 hours, until the two types of UV absorbers are completely melted into one phase, and then grind after cooling to obtain broadband UV absorber IV.

Examples and test results of the light-resistant polyolefin containing the ultraviolet absorber of the present invention are given below.

Example 1:

Compound (100phrPVC/2phr organotin heat stabilizer/0.5phr stearic acid/0.5phr light stabilizer, wherein the light stabilizer is a new type of UV absorber I, o-hydroxy phenyl salicylate (Phe), three One of the oxazine 5 (Tra)) was milled in twin rollers at about 170°C for about 8 minutes, and then molded at 180°C into sheets and plates of required thickness for testing. It was tested after accelerated ultraviolet light aging for 480h, and the test results are as follows:

Example 2:

Compounding material (100phrPVC/2phr organotin heat stabilizer/0.5phr stearic acid/0.5phr light stabilizer, wherein light stabilizer is novel ultraviolet absorber II, p-octylphenyl salicylate (Phobe) , 2-(2-Hydroxy-3,5-dicumylphenyl)-benzotriazole (UV234) is rolled in two rollers at about 170 ° C for about 8 minutes, and then molded at 180 ° C Sheets and panels of required thickness for testing purposes. It was tested after accelerated ultraviolet light aging for 480h, and the test results are as follows:

Example 3:

Add 0.5phr new UV absorber III to polypropylene, or 0.5phr p-tert-butylphenyl salicylate (Phbe), or 0.5phr 2-(2-hydroxy-3-tert-butyl-5- Methylphenyl)-5-chlorobenzotriazole (UV326), extruded and granulated by twin-screw extruder (processing temperatures are: 170°C, 190°C, 200°C, 200°C), and then at 200 Molded at ℃ into sheets and plates of required thickness for testing. It was tested after accelerated ultraviolet light aging for 480h, and the test results are as follows:

Example 4:

Add 0.5phr new UV absorber IV, or 0.5phr o-hydroxy phenyl salicylate (Phe), or 0.5phr2-(2-hydroxyl-3,5-dicumylphenyl)- Benzotriazole (UV234), extruded and granulated by twin-screw extruder (processing temperature: 170°C, 190°C, 200°C, 200°C), and then molded into a sheet of required thickness at 200°C and plates for testing purposes. It was tested after accelerated ultraviolet light aging for 480h, and the test results are as follows:

It is necessary to point out that the above examples are only used to further illustrate the present invention, and cannot be interpreted as limiting the protection scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention according to the above-mentioned content of the invention to implement.

Claims (3)

1. wideband ultraviolet absorber for polyolefin; The component that it is characterized in that this absorption agent consists of: salol compounds or derivatives thereof 0.25-0.5phr; Azimidobenzene compounds or compound in triazine class 0.5-0.75phr, said salol compounds and verivate thereof have following structure:

R wherein ₁For H ,-C (CH ₃) ₃With-C ₈H ₁₇In a kind of;

Said azimidobenzene compounds has following structure:

R wherein ₂Be Cl; R ₃For

In one of structure;

Said compound in triazine class has following structure:

R wherein ₄, R ₅And R ₆Be respectively

2. the method for preparing the said wideband ultraviolet absorber for polyolefin of claim 1; It is characterized in that the salol compounds or derivatives thereof heating pre-fusion of elder generation with proportional quantity; All change viscous liquid into until white crystal, add azimidobenzene compounds or compound in triazine class afterwards, abundant stirring reaction under 150～180 ℃; Until two complete mutually fusions is a phase, and cooling is after grinding promptly makes wideband ultraviolet absorber.

3. the preparation method of wideband ultraviolet absorber for polyolefin according to claim 2 is characterized in that said reaction stirring velocity is 50～300 rev/mins.

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