A polyolefin composite and a method for producing the same

Abstract

The application discloses a kind of polyolefin composite material and preparation method thereof, belong to the technical field of anti-tritium permeation composite material.The polyolefin composite material includes protective layer / barrier layer / protective layer.The protective layer includes: low-density polyethylene: 20-40 parts, high-density polyethylene: 20-40 parts, metallocene polyethylene: 10-30 parts, poly-1-butene: 5-10 parts, maleic anhydride grafted polyethylene: 3-5 parts, antioxidant: 0.5-1 part, rare earth oxide: 1-2 parts.The barrier layer includes: PVDC resin: 70-90 parts, EVA resin: 10-30 parts, antioxidant: 0.5-1 part, rare earth oxide: 1-2 parts.The polyolefin composite material has low tritium permeability and excellent low-temperature heat sealing, resistance to chemical permeability and interlayer bonding performance, and has wide application prospect in the preparation of anti-tritium permeation equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-tritium permeation composite material, in particular to a polyolefin composite material and a preparation method thereof. BACKGROUND

[0002] Tritium is a low-energy beta emitter with high specific activity, which is a low-toxicity and difficult-to-protect radionuclide. The main radiation hazards of tritium come from the internal radiation hazards caused by direct inhalation and skin absorption. In the personal safety protection of tritium, tritium glove box and tritium protective clothing are the main protective equipment, which can reduce the penetration and harm of tritium to human body to a certain extent, and have an irreplaceable role in tritium process and tritium protection.

[0003] When selecting tritium protective clothing, the permeability of the material is mainly considered. The tritium protective clothing is made of vulcanized rubber, cellophane, polyvinyl chloride, polyethylene and other high molecular materials. Since the permeability of tritium in the above materials is large, the performance requirements of tritium protective clothing cannot be met. At present, it is urgent to develop a new type of anti-tritium permeation composite material to meet the performance requirements of high-performance tritium protective clothing, which has important practical significance for the application of tritium protective clothing. SUMMARY

[0004] Therefore, the present application aims to solve the technical problem by providing a polyolefin composite material and a preparation method thereof. The polyolefin composite material has the advantages of good heat sealing, low tritium permeability and good chemical permeability.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a polyolefin composite material, which comprises a protective layer / barrier layer / protective layer.

[0007] The protective layer comprises the following components by weight:

[0008] Low-density polyethylene: 20-40 parts;

[0009] High-density polyethylene: 20-40 parts;

[0010] Metallocene polyethylene: 10-30 parts;

[0011] Poly-1-butene: 5-10 parts;

[0012] Maleic anhydride grafted polyethylene: 3-5 parts;

[0013] Antioxidant: 0.5-1 part;

[0014] Rare earth oxide: 1-2 parts;

[0015] The barrier layer comprises the following components by weight:

[0016] PVDC resin: 70-90 parts;

[0017] EVA resin: 10-30 parts;

[0018] Antioxidant: 0.5-1 part;

[0019] Rare earth oxide: 1-2 parts.

[0020] The present application modifies the resins of the protective layer and the barrier layer respectively, so that the polyolefin composite material has low tritium permeability and excellent low-temperature heat sealing property and interlayer bonding performance.

[0021] The low-density polyethylene and the high-density polyethylene in the protective layer above are complementary in performance.

[0022] The high-density polyethylene has a higher melting point than the low-density polyethylene, better heat resistance and better mechanical strength, while the low-density polyethylene has better processability and better flexibility, and the blending of the two can be complementary modified to make the polyolefin composite material have better mechanical properties and low-temperature heat sealing property.

[0023] The metallocene polyethylene, poly-1-butene and maleic anhydride grafted polyethylene synergistically improve the overall performance of the polyolefin composite material together with the low-density polyethylene and the high-density polyethylene above.

[0024] The PVDC resin and the EVA resin in the barrier layer above are blended to significantly improve the barrier performance of the composite material.

[0025] Preferably, the total thickness of the polyolefin composite material is 0.15-0.2 mm. In some specific embodiments of the present application, it is preferably 0.15 mm or 0.2 mm.

[0026] Preferably, the thickness of the protective layer is 35%-40% of the total thickness of the polyolefin composite material. In some specific embodiments of the present application, it is preferably 35% or 40%.

[0027] Preferably, the thickness of the barrier layer is 20%-30% of the total thickness of the polyolefin composite material. In some specific embodiments of the present application, it is preferably 20% or 30%.

[0028] Preferably, the content of methyl acrylate (MA) in the PVDC resin is 5wt%-10wt%. In some specific embodiments of the present application, it is preferably 5wt% or 10wt%.

[0029] Preferably, the content of vinyl acetate (VA) in the EVA resin is 10wt%-20wt%. In some specific embodiments of the present application, it is preferably 10wt% or 20wt%.

[0030] In some embodiments of the present application, the total thickness of the protective layer / barrier layer / protective layer is 0.2mm, and the thickness of the protective layer, the barrier layer, and the protective layer is 0.07mm, 0.06mm, and 0.07mm, respectively.

[0031] In some embodiments of the present application, the total thickness of the protective layer / barrier layer 1 / barrier layer 2 / heat-seal layer is 0.15mm, and the thickness of the protective layer, the barrier layer, and the protective layer is 0.06mm, 0.03mm, and 0.06mm, respectively.

[0032] Preferably, the low-density polyethylene resin has a melt index of 1-3g / 10min; more preferably, 1g / 10min or 3g / 10min.

[0033] Preferably, the high-density polyethylene resin has a melt index of 2-5g / 10min; more preferably, 2g / 10min or 5g / 10min.

[0034] Preferably, the metallocene polyethylene resin has a melt index of 5-8g / 10min; more preferably, 5g / 10min or 8g / 10min.

[0035] Preferably, the poly-1-butene resin has a melt index of 0.5-2g / 10min; more preferably, 0.5g / 10min or 2g / 10min.

[0036] Preferably, the maleic anhydride grafted polyethylene resin has a melt index of 2-10g / 10min; more preferably, 2g / 10min or 10g / 10min.

[0037] Preferably, the antioxidant is selected from one or more of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl ester, dilauryl thiodipropionate, tris(2,4-di-tert-butyl)phosphite;

[0038] Preferably, the rare earth oxide is selected from one or more of cerium oxide, gadolinium oxide, erbium oxide.

[0039] More preferably, the protective layer comprises the following ingredients by weight:

[0040] Low-density polyethylene: 20 parts;

[0041] High-density polyethylene: 40 parts;

[0042] Metallocene polyethylene: 10 parts;

[0043] Poly-1-butene: 10 parts;

[0044] Maleic anhydride grafted polyethylene: 5 parts;

[0045] Antioxidant: 1 part;

[0046] Rare earth oxide: 2 parts;

[0047] The barrier layer comprises the following components by weight parts:

[0048] PVDC resin: 90 parts;

[0049] EVA resin: 10 parts;

[0050] β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate: 1 part;

[0051] Cerium oxide 7: 2 parts.

[0052] The application further preferably, the protective layer, by weight parts, comprising the following components: low density polyethylene with a melt index of 1 g / 10 min: 20 parts;

[0053] High density polyethylene with a melt index of 2 g / 10 min: 40 parts;

[0054] Metallocene polyethylene with a melt index of 5 g / 10 min: 10 parts;

[0055] Polybutene-1 with a melt index of 0.5 g / 10 min: 10 parts;

[0056] Maleic anhydride grafted polyethylene with a melt index of 2 g / 10 min: 5 parts;

[0057] Antioxidant: 1 part;

[0058] Rare earth oxide: 2 parts;

[0059] The barrier layer comprises the following components by weight parts:

[0060] PVDC resin with a methyl acrylate content of 10 wt%: 90 parts;

[0061] EVA resin with a VA content of 20 wt%: 10 parts;

[0062] β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate: 1 part;

[0063] Cerium oxide: 2 parts.

[0064] The application is more preferably, the protective layer, by weight parts, comprising the following components: low density polyethylene: 30 parts;

[0065] High density polyethylene: 30 parts;

[0066] Metallocene polyethylene: 20 parts;

[0067] Polybutene-1: 7.5 parts;

[0068] Maleic anhydride grafted polyethylene: 4 parts;

[0069] BHT: 0.75 parts;

[0070] Cerium oxide: 1.5 parts;

[0071] The barrier layer comprises, by weight parts, the following components:

[0072] PVDC resin: 80 parts;

[0073] EVA resin: 20 parts;

[0074] BHT: 0.75 parts;

[0075] Cerium oxide: 1.5 parts.

[0076] Further preferably, the protective layer comprises, by weight parts, the following components: low density polyethylene with a melt index of 1 g / 10 min: 30 parts;

[0077] High density polyethylene with a melt index of 2 g / 10 min: 30 parts;

[0078] Metallocene polyethylene with a melt index of 5 g / 10 min: 20 parts;

[0079] Polybutene-1 with a melt index of 0.5 g / 10 min: 7.5 parts;

[0080] Maleic anhydride grafted polyethylene with a melt index of 2 g / 10 min: 4 parts; BHT: 0.75 parts;

[0081] Cerium oxide: 1.5 parts;

[0082] The barrier layer comprises, by weight parts, the following components:

[0083] PVDC resin with a MA content of 10 wt%: 80 parts;

[0084] EVA resin with a VA content of 20 wt%: 20 parts;

[0085] BHT: 0.75 parts;

[0086] Cerium oxide: 1.5 parts.

[0087] More preferably, the protective layer comprises, by weight parts: low density polyethylene: 40 parts;

[0088] high density polyethylene: 20 parts;

[0089] metallocene polyethylene: 30 parts;

[0090] polybutene-1: 5 parts;

[0091] maleic anhydride grafted polyethylene: 3 parts;

[0092] β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester: 0.5 parts;

[0093] cerium oxide: 1 part;

[0094] The barrier layer comprises, by weight parts: PVDC resin: 70 parts;

[0095] EVA resin: 30 parts;

[0096] EVA resin: 30 parts;

[0097] β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester: 0.5 parts;

[0098] cerium oxide: 1 part.

[0099] More preferably, the protective layer comprises, by weight parts: low density polyethylene with a melt index of 1 g / 10 min: 40 parts;

[0100] high density polyethylene with a melt index of 2 g / 10 min: 20 parts;

[0101] metallocene polyethylene with a melt index of 5 g / 10 min: 30 parts;

[0102] polybutene-1 with a melt index of 0.5 g / 10 min: 5 parts;

[0103] maleic anhydride grafted polyethylene with a melt index of 2 g / 10 min: 3 parts; β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester: 0.5 parts;

[0104] cerium oxide: 1 part;

[0105] The barrier layer comprises, by weight parts: PVDC resin with a MA content of 10 wt%: 70 parts;

[0106] EVA resin with a VA content of 20 wt%: 30 parts;

[0107] EVA resin with a VA content of 20 wt%: 30 parts;

[0108] β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl ester: 0.5 parts;

[0109] cerium oxide: 1 part.

[0110] More preferably, the protective layer comprises, by weight parts: low density polyethylene: 20 parts;

[0111] high density polyethylene: 40 parts;

[0112] metallocene polyethylene: 10 parts;

[0113] polybutene-1: 10 parts;

[0114] maleic anhydride grafted polyethylene: 5 parts;

[0115] dilauryl thiodipropionate: 1 part;

[0116] gadolinium oxide: 2 parts;

[0117] The barrier layer comprises, by weight parts:

[0118] PVDC resin: 90 parts;

[0119] EVA resin: 10 parts;

[0120] dilauryl thiodipropionate: 1 part;

[0121] gadolinium oxide: 2 parts.

[0122] More preferably, the protective layer comprises, by weight parts: low density polyethylene with a melt index of 3 g / 10 min: 20 parts;

[0123] high density polyethylene with a melt index of 5 g / 10 min: 40 parts;

[0124] metallocene polyethylene with a melt index of 8 g / 10 min: 10 parts;

[0125] polybutene-1 with a melt index of 2 g / 10 min: 10 parts;

[0126] maleic anhydride grafted polyethylene with a melt index of 10 g / 10 min: 5 parts;

[0127] dilauryl thiodipropionate: 1 part;

[0128] gadolinium oxide: 2 parts;

[0129] The barrier layer comprises, by weight parts:

[0130] PVDC resin with a MA content of 5 wt%: 90 parts;

[0131] EVA resin with VA content of 10 wt%: 10 parts;

[0132] dilauryl thiodipropionate: 1 part;

[0133] Gadolinium oxide: 2 parts.

[0134] More preferably, the protective layer comprises, by weight parts:

[0135] Low density polyethylene: 20 parts;

[0136] High density polyethylene: 40 parts;

[0137] Metallocene polyethylene: 10 parts;

[0138] Polybutene-1 : 10 parts;

[0139] Maleic anhydride grafted polyethylene: 5 parts;

[0140] Tris(2,4-di-tert-butyl) phenyl phosphite: 1 part;

[0141] Erbium oxide: 2 parts;

[0142] The barrier layer comprises, by weight parts:

[0143] PVDC resin: 90 parts;

[0144] EVA resin: 10 parts;

[0145] Tris(2,4-di-tert-butyl) phenyl phosphite: 1 part;

[0146] Erbium oxide: 2 parts.

[0147] More preferably, the protective layer comprises, by weight parts:

[0148] Low density polyethylene with melt index of 3 g / 10 min: 20 parts;

[0149] High density polyethylene with melt index of 5 g / 10 min: 40 parts;

[0150] Metallocene polyethylene with melt index of 8 g / 10 min: 10 parts;

[0151] Polybutene-1 with melt index of 2 g / 10 min: 10 parts;

[0152] Maleic anhydride grafted polyethylene with melt index of 10 g / 10 min: 5 parts;

[0153] Tris(2,4-di-tert-butyl) phenyl phosphite: 1 part;

[0154] Erbium oxide: 2 parts;

[0155] The barrier layer comprises the following components by weight:

[0156] PVDC resin with MA content of 5wt%: 90 parts;

[0157] EVA resin with VA content of 10wt%: 10 parts;

[0158] Tris (2, 4-di-tert-butyl) phenyl phosphite: 1 part;

[0159] Erbium oxide: 2 parts. The application also provides a preparation method of the polyolefin composite material, comprising the following steps:

[0160] 1) mixing low-density polyethylene, high-density polyethylene, metallocene polyethylene, poly-1-butene, maleic anhydride grafted polyethylene, antioxidant, and rare earth oxide, then extruding and granulating to obtain a modified resin for the protective layer;

[0161] 2) mixing PVDC resin, EVA resin, antioxidant, and rare earth oxide, then extruding and granulating to obtain a modified resin for the barrier layer;

[0162] 3) extruding the modified resin for the protective layer obtained in step 1), the modified resin for the barrier layer obtained in step 2), and the modified resin for the protective layer obtained in step 1) respectively to obtain a protective layer film, a barrier layer film, and a protective layer film, then stacking them in sequence, and then performing cooling, drawing, and winding to obtain the polyolefin composite material.

[0163] The above preparation method modifies the protective layer and the barrier layer to obtain the modified resin for the protective layer and the modified resin for the barrier layer.

[0164] Then, the polyolefin composite material of the application is prepared by using the method of multi-layer co-extrusion.

[0165] Preferably, in the step 1), the extrusion temperature is 180-220℃. In some specific embodiments of the application, the temperature is preferably 180℃, 200℃, or 220℃.

[0166] Preferably, in the step 1), the screw rotation speed is 50-70rpm / min; more preferably, the screw rotation speed is 50rpm / min, 60rpm / min, or 70rpm / min.

[0167] In the above preparation method, the extrusion temperature of the protective layer film in the step 2) is preferably 180-220℃, and the screw rotation speed is preferably 25-35r / min.

[0168] In some embodiments of the present application, the extrusion temperature of the protective layer film is 180℃, and the screw rotation speed is preferably 27r / min.

[0169] In some embodiments of the present application, the extrusion temperature of the protective layer film is 200℃, and the screw rotation speed is preferably 26r / min.

[0170] In some embodiments of the present application, the extrusion temperature of the protective layer film is 220℃, and the screw rotation speed is preferably 25r / min.

[0171] In some embodiments of the present application, the extrusion temperature of the protective layer film is 220℃, and the screw rotation speed is preferably 35r / min.

[0172] The extrusion temperature of the barrier layer film in step 2) is preferably 170-190℃, and the screw rotation speed is preferably 10-15r / min.

[0173] In some embodiments of the present application, the extrusion temperature of the barrier layer film is 170℃, and the screw rotation speed is preferably 20r / min.

[0174] In some embodiments of the present application, the extrusion temperature of the barrier layer film is 180℃, and the screw rotation speed is preferably 20r / min.

[0175] In some embodiments of the present application, the extrusion temperature of the barrier layer film is 190℃, and the screw rotation speed is preferably 15r / min.

[0176] In some embodiments of the present application, the extrusion temperature of the barrier layer film is 190℃, and the screw rotation speed is preferably 20r / min. The present application also provides a tritium permeation resistant equipment comprising the polyolefin composite material or the polyolefin composite material prepared by the above method.

[0177] The tritium permeation resistant equipment includes but is not limited to protective clothing, protective gloves, etc.

[0178] Compared with the prior art, the polyolefin composite provided by the application comprises a protective layer / barrier layer / protective layer. The protective layer comprises the following components in parts by weight: low-density polyethylene: 20-40 parts, high-density polyethylene: 20-40 parts, metallocene polyethylene: 10-30 parts, poly-1-butene: 5-10 parts, maleic anhydride grafted polyethylene: 3-5 parts, antioxidant: 0.5-1 part, and rare earth oxide: 1-2 parts. The barrier layer comprises the following components in parts by weight: PVDC resin: 70-90 parts, EVA resin: 10-30 parts, antioxidant: 0.5-1 part, and rare earth oxide: 1-2 parts. The polyolefin composite provided by the application has low tritium permeability and excellent low-temperature heat sealing property, chemical permeation resistance and interlayer bonding performance by modifying the protective layer and the barrier layer respectively. DETAILED DESCRIPTION

[0179] In order to further illustrate the application, the polyolefin composite provided by the application and the preparation method thereof are described in detail below in combination with examples.

[0180] Example 1

[0181] (1) Preparation of modified resin for protective layer

[0182] Low-density polyethylene with a melt index of 1 g / 10 min: 20 parts, high-density polyethylene with a melt index of 2 g / 10 min: 40 parts, metallocene polyethylene with a melt index of 5 g / 10 min: 10 parts, poly-1-butene with a melt index of 0.5 g / 10 min: 10 parts, maleic anhydride grafted polyethylene with a melt index of 2 g / 10 min: 5 parts, β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate: 1 part, and cerium oxide: 2 parts.

[0183] The raw materials are weighed according to the above proportions, poured into a mixer, the stirring speed is controlled at 400 rpm / min, the dispersion speed is controlled at 800 rpm / min, and the stirring time is controlled at 10 min. After mixing uniformly, the above raw materials are added to a twin-screw extruder, the temperature is controlled at 220°C, and the screw speed is controlled at 70 rpm / min, mixing and granulation are performed, and the modified resin for the protective layer is obtained.

[0184] (2) Preparation of modified resin for barrier layer

[0185] PVDC resin with a MA (methyl acrylate) content of 10%: 90 parts, EVA resin with a VA content of 20%: 10 parts, β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate: 1 part, and cerium oxide: 2 parts.

[0186] The raw materials were weighed according to the above-mentioned proportions, poured into a mixer, the stirring speed was controlled at 400 rpm / min, the dispersing speed was controlled at 800 rpm / min, and the stirring time was controlled at 10 min. After mixing uniformly, the above-mentioned raw materials were added into a twin-screw extruder, the temperature was controlled at 190°C, and the screw speed was controlled at 60 rpm / min, to carry out mixing and granulation, thereby obtaining the modified resin for the protective layer.

[0187] (3) Preparation of polyolefin composite material

[0188] The modified resin for the protective layer, the modified resin for the barrier layer and the modified resin for the protective layer were respectively added into three single-screw extruders A, B and C of the co-extrusion molding device. The temperature of the body of the single-screw extruder A was 220°C, and the screw speed was 25 r / min; the temperature of the body of the single-screw extruder B was 190°C, and the screw speed was 20 r / min; the temperature of the body of the single-screw extruder C was 220°C, and the screw speed was 25 r / min. The polymer melts were respectively extruded into the die by the corresponding extruders to be laminated, thereby obtaining a film blank. The film blank was subjected to cooling, drawing and winding treatment to obtain a polyolefin composite material with a total thickness of 0.2 mm (the thickness of layer A accounted for 35% of the total thickness of the composite film, the thickness of layer B accounted for 30% of the total thickness of the composite film, and the thickness of layer C accounted for 35% of the total thickness of the composite film).

[0189] Example 2

[0190] (1) Preparation of modified resin for protective layer

[0191] Low-density polyethylene with a melt index of 1 g / 10 min 30 parts, high-density polyethylene with a melt index of 2 g / 10 min 30 parts, metallocene polyethylene with a melt index of 5 g / 10 min 20 parts, polybutene-1 with a melt index of 0.5 g / 10 min 7.5 parts, maleic anhydride grafted polyethylene with a melt index of 2 g / 10 min 4 parts, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester 0.75 parts, cerium oxide 1.5 parts.

[0192] The raw materials were weighed according to the above-mentioned proportions, poured into a mixer, the stirring speed was controlled at 400 rpm / min, the dispersing speed was controlled at 800 rpm / min, and the stirring time was controlled at 10 min. After mixing uniformly, the above-mentioned raw materials were added into a twin-screw extruder, the temperature was controlled at 190°C, and the screw speed was controlled at 60 rpm / min, to carry out mixing and granulation, thereby obtaining the modified resin for the protective layer.

[0193] (2) Preparation of modified resin for barrier layer

[0194] MA (methyl acrylate) content 10% of PVDC resin 80 parts, VA content 20% of EVA resin 20 parts, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester 0.75 parts, cerium oxide 1.5 parts.

[0195] The raw materials are weighed according to the above proportions, poured into a mixer, the stirring speed is controlled at 300 rpm / min, the dispersion speed is controlled at 600 rpm / min, and the stirring time is controlled at 7.5 min. After mixing uniformly, the above raw materials are added to a twin-screw extruder, the temperature is controlled at 180°C, and the screw speed is controlled at 50 rpm / min, to carry out mixing and granulation to obtain the modified resin for the protective layer.

[0196] (3) Preparation of polyolefin composite material

[0197] The modified resin for the protective layer, the modified resin for the barrier layer, and the modified resin for the protective layer are respectively added to three single-screw extruders A, B, and C of the co-extrusion molding device. The temperature of the body of the single-screw extruder A is 200°C, and the screw speed is 26 r / min; the temperature of the body of the single-screw extruder B is 180°C, and the screw speed is 20 r / min; the temperature of the body of the single-screw extruder C is 200°C, and the screw speed is 26 r / min. The polymer melts are respectively extruded into the die by the corresponding extruders to be laminated to obtain a film blank, and the film blank is subjected to cooling, drawing, and winding treatment to obtain a polyolefin composite material with a total thickness of 0.2 mm (the thickness of layer A accounts for 35% of the total thickness of the composite film, the thickness of layer B accounts for 30% of the total thickness of the composite film, and the thickness of layer C accounts for 35% of the total thickness of the composite film).

[0198] Example 3

[0199] (1) Preparation of modified resin for protective layer

[0200] Low-density polyethylene with a melt index of 1 g / 10 min 40 parts, high-density polyethylene with a melt index of 2 g / 10 min 20 parts, metallocene polyethylene with a melt index of 5 g / 10 min 30 parts, poly-1-butene with a melt index of 0.5 g / 10 min 5 parts, maleic anhydride grafted polyethylene with a melt index of 2 g / 10 min 3 parts, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester 0.5 parts, cerium oxide 1 part.

[0201] The raw materials are weighed according to the above proportions, poured into a mixer, the stirring speed is controlled at 200 rpm / min, the dispersion speed is controlled at 500 rpm / min, and the stirring time is controlled at 5 min. After mixing uniformly, the above raw materials are added to a twin-screw extruder, the temperature is controlled at 180°C, and the screw speed is controlled at 50 rpm / min, to carry out mixing and granulation to obtain the modified resin for the protective layer.

[0202] (2) Preparation of the barrier layer modifying resin

[0203] PVDC resin with MA (methyl acrylate) content of 10% 70 parts, EVA resin with VA content of 20% 30 parts, β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester 0.5 parts, cerium oxide 1 part.

[0204] The raw materials are weighed according to the above proportions, poured into a mixer, the stirring speed is controlled at 200 rpm / min, the dispersion speed is controlled at 500 rpm / min, and the stirring time is controlled at 5 min. After mixing uniformly, the above raw materials are added to a twin-screw extruder, the temperature is controlled at 170°C, and the screw speed is controlled at 40 rpm / min, mixing and granulation are carried out, and the modified resin for the protective layer is obtained.

[0205] (3) Preparation of the polyolefin composite material

[0206] The modified resin for the protective layer, the modified resin for the barrier layer, and the modified resin for the protective layer are respectively added to the three single-screw extruders A, B, and C of the co-extrusion molding device. The temperature of the body of the single-screw extruder A is 180°C, and the screw speed is 27 r / min; the temperature of the body of the single-screw extruder B is 170°C, and the screw speed is 20 r / min; the temperature of the body of the single-screw extruder C is 180°C, and the screw speed is 27 r / min. The polymer melt is respectively extruded into the die by the corresponding extruder for lamination, and a film blank is obtained. The film blank is cooled, drawn, and wound to obtain a polyolefin composite material with a total thickness of 0.2 mm (the thickness of layer A accounts for 35% of the total thickness of the composite film, the thickness of layer B accounts for 30% of the total thickness of the composite film, and the thickness of layer C accounts for 35% of the total thickness of the composite film).

[0207] Example 4

[0208] (1) Preparation of the modified resin for the protective layer

[0209] Low-density polyethylene with a melt index of 3 g / 10 min 20 parts, high-density polyethylene with a melt index of 5 g / 10 min 40 parts, metallocene polyethylene with a melt index of 8 g / 10 min 10 parts, poly-1-butene with a melt index of 2 g / 10 min 10 parts, maleic anhydride grafted polyethylene with a melt index of 10 g / 10 min 5 parts, dilauryl thiodipropionate 1 part, gadolinium oxide 2 parts.

[0210] The raw materials were weighed according to the above proportions, poured into a mixer, the stirring speed was controlled at 400 rpm / min, the dispersion speed was controlled at 800 rpm / min, and the stirring time was controlled at 10 min. After mixing uniformly, the above raw materials were added to a twin-screw extruder, the temperature was controlled at 220°C, and the screw speed was controlled at 70 rpm / min, to carry out mixing and granulation, and a modified resin for the protective layer was obtained.

[0211] (2) Preparation of modified resin for barrier layer

[0212] 90 parts of PVDC resin with a MA (methyl acrylate) content of 5%, 10 parts of EVA resin with a VA content of 10%, 1 part of dilauryl thiodipropionate, and 2 parts of gadolinium oxide.

[0213] The raw materials were weighed according to the above proportions, poured into a mixer, the stirring speed was controlled at 400 rpm / min, the dispersion speed was controlled at 800 rpm / min, and the stirring time was controlled at 10 min. After mixing uniformly, the above raw materials were added to a twin-screw extruder, the temperature was controlled at 190°C, and the screw speed was controlled at 60 rpm / min, to carry out mixing and granulation, and a modified resin for the protective layer was obtained.

[0214] (3) Preparation of polyolefin composite material

[0215] The modified resin for the protective layer, the modified resin for the barrier layer, and the modified resin for the protective layer were added to three single-screw extruders A, B, and C of a co-extrusion device, respectively. The temperature of the body of the single-screw extruder A was 220°C, and the screw speed was 35 r / min; the temperature of the body of the single-screw extruder B was 190°C, and the screw speed was 15 r / min; and the temperature of the body of the single-screw extruder C was 220°C, and the screw speed was 35 r / min. The polymer melts were extruded from the corresponding extruders into a die to be laminated, to obtain a film blank, and the film blank was cooled, drawn, and wound to obtain a polyolefin composite material with a total thickness of 0.15 mm (the thickness of layer A accounted for 40% of the total thickness of the composite film, the thickness of layer B accounted for 20% of the total thickness of the composite film, and the thickness of layer C accounted for 40% of the total thickness of the composite film).

[0216] Example 5

[0217] (1) Preparation of modified resin for protective layer

[0218] 20 parts of low-density polyethylene with a melt index of 3 g / 10 min, 40 parts of high-density polyethylene with a melt index of 5 g / 10 min, 10 parts of metallocene polyethylene with a melt index of 8 g / 10 min, 10 parts of poly-1-butene with a melt index of 2 g / 10 min, 5 parts of maleic anhydride grafted polyethylene with a melt index of 10 g / 10 min, 1 part of tris (2, 4-di-tert-butyl) phenyl phosphite, and 2 parts of erbium oxide.

[0219] The raw materials were weighed according to the above-mentioned proportions, poured into a mixer, the stirring speed was controlled at 400 rpm / min, the dispersion speed was controlled at 800 rpm / min, and the stirring time was controlled at 10 min. After mixing uniformly, the above-mentioned raw materials were added to a twin-screw extruder, the temperature was controlled at 220°C, and the screw speed was controlled at 70 rpm / min, to carry out mixing and granulation, to obtain the modified resin for the protective layer.

[0220] (2) Preparation of the modified resin for the barrier layer

[0221] 90 parts of PVDC resin with a MA (methyl acrylate) content of 5%, 10 parts of EVA resin with a VA content of 10%, 1 part of tris (2, 4-di-tert-butyl) phenyl phosphite, and 2 parts of erbium oxide.

[0222] The raw materials were weighed according to the above-mentioned proportions, poured into a mixer, the stirring speed was controlled at 400 rpm / min, the dispersion speed was controlled at 800 rpm / min, and the stirring time was controlled at 10 min. After mixing uniformly, the above-mentioned raw materials were added to a twin-screw extruder, the temperature was controlled at 190°C, and the screw speed was controlled at 60 rpm / min, to carry out mixing and granulation, to obtain the modified resin for the protective layer.

[0223] (3) Preparation of the polyolefin composite material

[0224] The modified resin for the protective layer, the modified resin for the barrier layer, and the modified resin for the protective layer were respectively added to three single-screw extruders A, B, and C of a co-extrusion device. The temperature of the body of the single-screw extruder A was 220°C, and the screw speed was 35 r / min; the temperature of the body of the single-screw extruder B was 190°C, and the screw speed was 15 r / min; and the temperature of the body of the single-screw extruder C was 220°C, and the screw speed was 35 r / min. The polymer melt was respectively extruded into a die by the corresponding extruder to be laminated, to obtain a film blank, and the film blank was subjected to cooling, drawing, and winding treatment to obtain a polyolefin composite material with a total thickness of 0.15 mm (the thickness of layer A accounted for 40% of the total thickness of the composite film, the thickness of layer B accounted for 20% of the total thickness of the composite film, and the thickness of layer C accounted for 40% of the total thickness of the composite film).

[0225] Comparative Example 1

[0226] (1) Preparation of the modified resin for the protective layer

[0227] Low density polyethylene with melt index of 1 g / 10 min 20 parts, high density polyethylene with melt index of 2 g / 10 min 40 parts, metallocene polyethylene with melt index of 5 g / 10 min 10 parts, polybutene-1 with melt index of 0.5 g / 10 min 10 parts, maleic anhydride grafted polyethylene with melt index of 2 g / 10 min 5 parts, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl ester 1 part, cerium oxide 2 parts.

[0228] The raw materials were weighed according to the above-mentioned proportions, poured into a mixer, the stirring speed was controlled at 400 rpm / min, the dispersion speed was controlled at 800 rpm / min, and the stirring time was controlled at 10 min. After mixing uniformly, the above-mentioned raw materials were added to a twin-screw extruder, the temperature was controlled at 220°C, and the screw speed was controlled at 70 rpm / min, to carry out mixing and granulation, and a modified resin for a protective layer was obtained.

[0229] (2) Preparation of comparative sample

[0230] The modified resin for a protective layer was added to three single-screw extruders A, B and C of a co-extrusion device. The temperature of the body of single-screw extruder A was 220°C, and the screw speed was 25 r / min; the temperature of the body of single-screw extruder B was 220°C, and the screw speed was 25 r / min; the temperature of the body of single-screw extruder C was 220°C, and the screw speed was 25 r / min. The polymer melts were respectively extruded into a die by the corresponding extruders to be laminated, to obtain a film blank, and the film blank was subjected to cooling, drawing and winding treatment to obtain a comparative sample 1 with a total thickness of 0.2 mm.

[0231] Comparative example 2

[0232] Low density polyethylene with melt index of 1 g / 10 min, PVDC resin with MA (methyl acrylate) content of 10% and low density polyethylene with melt index of 1 g / 10 min were added to three single-screw extruders A, B and C of a co-extrusion device. The temperature of the body of single-screw extruder A was 220°C, and the screw speed was 25 r / min; the temperature of the body of single-screw extruder B was 190°C, and the screw speed was 20 r / min; the temperature of the body of single-screw extruder C was 220°C, and the screw speed was 25 r / min. The polymer melts were respectively extruded into a die by the corresponding extruders to be laminated, to obtain a film blank, and the film blank was subjected to cooling, drawing and winding treatment to obtain a comparative sample 2 with a total thickness of 0.2 mm (the thickness of layer A accounted for 35% of the total thickness of the composite film, the thickness of layer B accounted for 30% of the total thickness of the composite film, and the thickness of layer C accounted for 35% of the total thickness of the composite film).

[0233] The properties of the polyolefin composite materials prepared in the above-mentioned examples 1-5 and comparative examples 1-2 were tested, and the test results are shown in Table 1.

[0234] Table 1. Polyolefin composite properties

[0235]

[0236] The above description of the embodiments is only for the purpose of helping understand the method of the present application and its core idea. It should be noted that, for those skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A polyolefin composite, characterized by, The protective layer / barrier layer / protective layer; The protective layer comprises the following ingredients by weight: Low-density polyethylene: 20-40 parts; High-density polyethylene: 20-40 parts; Metallocene polyethylene: 10-30 parts; Poly-1-butene: 5-10 parts; Maleic anhydride grafted polyethylene: 3-5 parts; Antioxidant: 0.5-1 part; Rare earth oxide: 1-2 parts; The barrier layer comprises the following ingredients by weight: PVDC resin: 70-90 parts; EVA resin: 10-30 parts; Antioxidant: 0.5-1 part; Rare earth oxide: 1-2 parts.

2. The polyolefin composite of claim 1, wherein, The total thickness of the polyolefin composite is 0.15-0.2 mm; The thickness of the protective layer is 35%-40% of the total thickness of the polyolefin composite; The thickness of the barrier layer is 20%-30% of the total thickness of the polyolefin composite for preventing tritium permeation.

3. The polyolefin composite of claim 1, wherein, The content of methyl acrylate in the PVDC resin is 5wt%-10wt%; The content of vinyl acetate in the EVA resin is 10wt%-20wt%; The melt index of the low-density polyethylene resin is 1-3 g / 10min; The melt index of the high-density polyethylene resin is 2-5 g / 10min; The melt index of the metallocene polyethylene resin is 5-8 g / 10min; The melt index of the poly-1-butene resin is 0.5-2 g / 10min; The melt index of the maleic anhydride grafted polyethylene resin is 2-10 g / 10min; The antioxidant is selected from one or more of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecanol, dilauryl thiodipropionate, and tris(2,4-di-tert-butyl) phenyl phosphite; The rare earth oxide is selected from one or more of cerium oxide, gadolinium oxide, and erbium oxide.

4. The polyolefin composite of claim 1, wherein, The protective layer comprises the following ingredients by weight: Low-density polyethylene: 20 parts; High-density polyethylene: 40 parts; Metallocene polyethylene: 10 parts; Poly-1-butene: 10 parts; Maleic anhydride grafted polyethylene: 5 parts; Antioxidant: 1 part; Rare earth oxide: 2 parts; The barrier layer comprises the following ingredients by weight: PVDC resin: 90 parts; EVA resin: 10 parts; β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecanol: 1 part; Cerium oxide: 2 parts.

5. The polyolefin composite of claim 1, wherein, The protective layer comprises the following ingredients by weight: Low-density polyethylene: 30 parts; High-density polyethylene: 30 parts; Metallocene polyethylene: 20 parts; Poly-1-butene: 7.5 parts; Maleic anhydride grafted polyethylene: 4 parts; Antioxidant: 0.75 parts; Rare earth oxide: 1.5 parts; The barrier layer comprises the following ingredients by weight: PVDC resin: 80 parts; EVA resin: 20 parts; β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate octadecanol: 0.75 parts; Cerium oxide: 1.5 parts.

6. The polyolefin composite of claim 1, wherein, The protective layer comprises the following ingredients by weight: Low-density polyethylene: 40 parts; High-density polyethylene: 20 parts; Metallocene polyethylene: 30 parts; Poly-1-butene: 5 parts; Maleic anhydride grafted polyethylene: 3 parts; Antioxidant: 0.5 parts; Rare earth oxide: 1 part; The barrier layer comprises the following components by weight: PVDC resin: 70 parts; EVA resin: 30 parts; β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate: 0.5 parts; Cerium oxide: 1 part.

7. The polyolefin composite of claim 1, wherein, The protective layer comprises the following components by weight: Low-density polyethylene: 20 parts; High-density polyethylene: 40 parts; Metallocene polyethylene: 10 parts; Poly-1-butene: 10 parts; Maleic anhydride grafted polyethylene: 5 parts; Dilauryl thiodipropionate: 1 part; Gadolinium oxide: 2 parts; The barrier layer comprises the following components by weight: PVDC resin: 90 parts; EVA resin: 10 parts; Dilauryl thiodipropionate: 1 part; Gadolinium oxide: 2 parts.

8. The polyolefin composite of claim 1, wherein, The protective layer comprises the following components by weight: Low-density polyethylene: 20 parts; High-density polyethylene: 40 parts; Metallocene polyethylene: 10 parts; Poly-1-butene: 10 parts; Maleic anhydride grafted polyethylene: 5 parts; Tris(2,4-di-tert-butyl) phenyl phosphite: 1 part; Erbium oxide: 2 parts; The barrier layer comprises the following components by weight: PVDC resin: 90 parts; EVA resin: 10 parts; Tris(2,4-di-tert-butyl) phenyl phosphite: 1 part; Erbium oxide: 2 parts.

9. A process for the production of a polyolefin composite according to any one of claims 1 to 8, characterized in that The method comprises the following steps: 1) mixing low-density polyethylene, high-density polyethylene, metallocene polyethylene, poly-1-butene, maleic anhydride grafted polyethylene, antioxidant, and rare earth oxide, extruding and granulating to obtain modified resin for the protective layer; 2) mixing PVDC resin, EVA resin, antioxidant, and rare earth oxide, extruding and granulating to obtain modified resin for the barrier layer; 3) extruding the modified resin for the protective layer obtained in step 1), the modified resin for the barrier layer obtained in step 2), and the modified resin for the protective layer obtained in step 1) to obtain protective layer film, barrier layer film, and protective layer film respectively, then stacking them in sequence, and then performing cooling, drawing, and winding to obtain the polyolefin composite material.

10. A tritium permeation resistant apparatus, characterized by, The polyolefin composite material is prepared by the method of any one of claims 1-8 or the method of claim 9.

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