RU2429189C1 - Polymeric nanocomposition for protection from uv radiation - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: composition contains polyolefin or a copolymer of olefin and a UV absorber. The UV absorber is nanosized silicon with specific surface area of 36-97 m²/g in amount of 0.1-1.0 wt % and integral transmission of 80-2.5%.

EFFECT: polymeric nanocomposition enables to obtain film materials with a wide spectral range of absorption of medium-wave UV radiation.

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Description

The invention relates to polymeric film materials that protect against UV radiation and photochemical aging.

Known polymer film material for enclosing greenhouses, obtained from a composition comprising high pressure polyethylene or a copolymer of ethylene with vinyl acetate in an amount of 99.0-99.2 wt.% And benzene OA in an amount of 0.8-1.0 wt.%. [patent 94027744, Russia, IPC C08J 5/18, C08L 23/06, publ. 06/20/1996].

The disadvantage of this invention is the relatively narrow spectral range of absorption of UV radiation (290-330 nm), high spectral transmittance for UV (up to 15%) and the technologically unsuccessful stage of preliminary cold mixing of UV absorber powder with polymer granules, which gives a poor distribution of particles in the polymer film compared to the present invention.

The closest set of essential features to the claimed material is a composition that protects against UV radiation, including an organic thermoplastic polymeric material, preferably a polyolefin in an amount of 981 or 985 g, an oligoester or polyester of the claimed formula in an amount of 13 g and micronized zinc oxide in an amount 6 g or micronized titanium dioxide in an amount of 2 g. A linear low-density polyethylene with a density of 0.919 g / cm ³ and flow index is used as the polyolefin the melt (190 ° C, 2.16 kg) equal to 1.1. The mixture is extruded at 230 ° C. on a twin screw extruder. The obtained granules are blown (using a laboratory extruder with a blower) at 230 ° C and get a film with a thickness of about 50 microns [patent 2370502, Russia, IPC C08G 63/685, C08K 5/10, C08K 5/3492, publ. 07/10/2007].

The disadvantage of this invention is the relatively narrow range of UV transmittance (280-390 nm) and higher spectral transmittance (from 9.9 to 91.0%) compared with the present invention.

The technical result of the invention is the creation of a film material with an extended spectral range of absorption of medium-wave UV radiation (200-420 nm), which reduces the yield of vegetable crops due to the cost of part of the growth energy of plants to protect against it, reduces the shelf life of food products, worsens performance electronic industry products.

The specified technical result is achieved due to the fact that the polymer composition for protection against UV radiation contains as a polymer matrix a polyolefin or an olefin-based copolymer (high pressure polyethylene (LDPE), melting point (max) 104 ° C, melt index 2.0 g / 10 min, density 0.91 g / cm ³ , molecular weight 20,000-24,000; ethylene vinyl acetate copolymer (SEVA), vinyl acetate content 20-30 wt.%, melting point 70-85 ° C, melt index 20-80 g / 10 min, density of 0,93-0,95 g / cm ³ low-density polyethylene (HDPE), the melting temperature Ia (max) 114-120 ° C, a melt index of 1.5-3.0 g / 10 min, density 0.93 g / cm ^3, molecular weight 25000-30000; polypropylene (PP), melting temperature (max) 140 -145 ° C, melt index 3.0 g / 10 min, density 0.85 g / cm ³ ) and the active substance is polydispersed nanocrystalline silicon with a specific surface area of 36-97 m ² / g, encapsulated in a shell of oxide, silicon dioxide or their phases of variable composition of nitride, silicon oxynitride or their phases of variable composition, characterized by a directionally variable distribution function of the size of the particles of the core nanocomposite th material [I.A. Tutorsky, A.I. Belogorokhov, A. A. Ishenko, P. A. Storozhenko. The structure and adsorption properties of nanocrystalline silicon. - Colloid. Journal, (2005) 67, 4, 541-547. Bagratashvili V.N., Belogorokhov A.I., Ischenko A.A., Storozhenko P.A., Tutorsky I.A. Control of the spectral characteristics of multiphase ultrafine systems based on nanocrystalline silicon in the UV wavelength range // DAN. (2005) 405, No. 3. S.360-363].

A method of obtaining the inventive polymer film material includes hot mixing granular polymer in an amount of 99.0-99.9 wt.% And nanosized silicon 0.1-1.0 wt.% At 120-130 ° C for a copolymer with vinyl acetate, 140-150 ° C for high pressure polyethylene, 160-170 ° C for low pressure polyethylene, 170-180 ° C for polypropylene and 160-180 ° C for polymer mixtures for 5-10 minutes until a homogeneous mixture is formed, or a superconcentrate containing 5 -15 wt.% Nanosized silicon and 95-85% polymer or polymer mixture under the same conditions. Then the composite material is heated to 200-230 ° C for a mixture with polypropylene, 190-210 ° C for a mixture with low pressure polyethylene and polymer compositions, 170-190 ° C for a mixture with high pressure polyethylene and 130-140 ° C for a copolymer mixture ethylene with vinyl acetate and form the film by extrusion of the melt under pressure.

The technical result provided by the claimed invention, a film of polymeric material, is expressed in the reduction of the spectral transmittance of the material in zone B of UV radiation from 80 to almost 0% when nanosized silicon particles are introduced into the polymer in an amount of 0.1-1.0 wt.% (At film thickness 50-100 microns).

Examples of the invention.

Example 1

Preliminary hot mixing of granular high-pressure polyethylene in an amount of 99.0 and nanosized silicon with a specific surface of 36 m ² / g in an amount of 1.0 wt.% In an open mixer (roll) or closed type (twin screw extruder, cam chamber) is carried out for 5-10 minutes until a homogeneous mixture is formed. Mixing is carried out at temperatures from 140 to 150 ° C. The prepared mixture is granulated and then fed to the extruder to obtain a flat or tubular film. The temperature conditions of film formation on the ARP-20-25 extrusion plant (Russia) are in the range of 170-190 ° С.

Example 2

Analogously to example 1, only the content of nanoscale silicon 0.1%.

Example 3

Analogously to example 1, only PP is selected as a polymer.

Example 4

Analogously to example 1, only nanosized silicon is taken with a specific surface of 97 m ² / g in an amount of 0.5%.

Example 5

Analogously to example 4, only a copolymer of ethylene with vinyl acetate was taken as a polymer.

Example 6

Analogously to example 1, only as a polymer, a mixture of high pressure polyethylene and a copolymer of ethylene with vinyl acetate (in the ratio 1: 1) was selected.

The values of the integral transmittance of the samples are given in the table.

Table. Sample Integral Transmission Values No. Sample The value of the integrated transmission,% 200-420 nm 430-700 nm one Example 1 5,0 20,0-40,0 2 Example 2 80.0 90.0-95.0 3 Example 3 5,0 20,0-40,0 four Example 4 3.0 20,0-40,0 5 Example 5 2.5 20,0-40,0 6 Example 6 4.0 20,0-40,0

The proposed polymer nanocomposition will allow to obtain film and other materials with a wide spectral range of absorption of medium-wave UV radiation (200-420 nm). This invention will find application in agriculture (greenhouse films) and the packaging industry (for packaging food, electronic products, etc.).

Claims (1)

A polymer nanocomposite that protects against UV radiation, including a polyolefin or an olefin copolymer, characterized in that nanosized silicon with a specific surface of 36-97 m ² / g in an amount of 0.1-1.0 wt.% Is taken as a UV absorber and the absorption range of UV radiation and the value of the integral transmittance are 200-420 nm and 80-2.5%, respectively.