Polyethylene radiation-proof sheet and preparation process thereof

Abstract

The present invention relates to the technical field of polymer materials, and in particular to a polyethylene radiation-proof sheet and a preparation process thereof. Its preparation process comprises the following steps: barite powder modification; barite powder surface coating resin to prepare interlayer material; outer polyethylene sheet preparation; composite sheet assembly. The present invention modifies barite powder to make an interlayer material to prepare a polyethylene radiation-proof sheet. Since barite has good absorption capacity for X-rays and gamma rays, barite is added when making radiation-proof sheets, which can significantly improve the radiation-proof performance of the sheet, and barite can also be used as a filler for the interlayer of the sheet. Barite itself has a high density, and adding it to the sheet can effectively increase the density and physical properties of the sheet.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a polyethylene radiation-proof plate and a preparation process thereof. Background Art

[0002] Polyethylene sheet is a sheet made of polyethylene (PE) material. Due to its good chemical stability and physical properties, this material is widely used in chemical, food, water treatment, electronic equipment, aerospace and other industries.

[0003] Radiation protection is required in special environments such as nuclear facilities and hospital radiology departments. Polyethylene sheets can be used as part of walls, floors or equipment casings to provide necessary protection. However, the protective capabilities of polyethylene sheets themselves are limited, and they are often combined with other materials such as lead sheets for protection. However, the cost of lead sheets is relatively high, and my country's lead ore reserves are limited. Therefore, other materials are needed to replace lead sheets to provide radiation protection. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention aims to provide a polyethylene radiation-proof plate and a preparation process thereof.

[0005] A preparation process of a polyethylene radiation-proof sheet material comprises the following steps:

[0006] S1: Barite powder modification

[0007] Weigh barite powder and coupling agent stearic acid, add them dropwise while stirring the barite powder in a high-speed mixer, then heat and react, discharge the material in the high-speed mixer, and obtain modified barite powder;

[0008] S2: Barite powder surface coated with resin to prepare interlayer material

[0009] Hexamethyldisiloxane, vinyl double-cap, deionized water, anhydrous ethanol and toluene are added into a reaction bottle, and the temperature is raised, and then ethyl orthosilicate is added dropwise to prepare a resin block, the resin block is crushed, ground and sieved to obtain resin particles, the resin particles are mixed and ground with modified barite powder to obtain a mixed powder, and the mixed powder is molded to obtain a sandwich material;

[0010] S3: Preparation of outer polyethylene sheet

[0011] Pour polyethylene powder particles into the mold, melt them through the action of the pulse vibration force field to form a well-welded melt billet, take the melt billet out of the mold, then quickly cut and fold the melt billet in half, and put the folded melt billet back into the center of the mold; apply static pressure to the folded melt billet to reheat it, apply pressure to the reheated melt billet, repeat this step 2-4 times, cool the mold, and obtain a polyethylene sheet;

[0012] S4: Composite panel assembly

[0013] The two polyethylene sheets prepared in step S3 are adhered to the front and back sides of the sandwich material by an adhesive, and a pressure of 15-20 MPa is applied for 1-3 minutes to obtain a polyethylene radiation-proof sheet.

[0014] Furthermore, step S1 of barite powder modification comprises the following steps:

[0015] S1.1: Weigh 95-100 parts by weight of barite powder and 5-10 parts by weight of coupling agent stearic acid, and add them dropwise while stirring the barite powder in a high-speed mixer;

[0016] S1.2: Then heat to 70-75°C and react for 10-30 minutes, discharge the material in the high-speed mixer to obtain modified barite powder.

[0017] Furthermore, step S2, coating the surface of the barite powder with resin to prepare an interlayer material, comprises the following steps:

[0018] S2.1: Add hexamethyldisiloxane, vinyl double cap, deionized water, anhydrous ethanol and toluene into a reaction bottle, stir at a speed of 300-350r / min, and simultaneously drop dilute hydrochloric acid, slowly raise the temperature to 50-55°C, and then drop 1-5% of the total volume of tetraethyl orthosilicate into the reaction bottle;

[0019] S2.2: Then continue to raise the temperature to 70-75°C, react for 2-2.5h, and then cool to 50°C;

[0020] S2.3: Add toluene to the reaction flask for extraction for 2-2.5 hours, cool to room temperature, wash the obtained extract with water until neutral, dry with anhydrous calcium chloride, filter to remove salt, and remove the solvent by rotary evaporation to obtain a resin block;

[0021] S2.4: crush the resin block and grind it through a 120-mesh sieve to obtain resin particles, mix the resin particles with modified barite powder and grind them to obtain a mixed powder, press the mixed powder into a mold at a pressure of 40 MPa, and cure it for 7-8 days to obtain a sandwich material.

[0022] Furthermore, in step S2.1, the volume ratio of hexamethyldisiloxane, vinyl double head, deionized water, anhydrous ethanol and toluene is 1:1:(2-4):(1-3):(2-3).

[0023] Furthermore, in step S2.4, the mass ratio of the resin particles to the modified barite powder is (2-3):1.

[0024] Furthermore, step S3 of preparing the outer polyethylene sheet comprises the following steps:

[0025] S3.1: Pour polyethylene powder particles into the mold, and after being subjected to the pulse force field for 3-5 minutes, quickly heat up to 190-220°C to melt and form a well-welded melt blank;

[0026] S3.2: Take the melt billet out of the mold, then quickly cut and fold the melt billet in half, and put the folded melt billet back into the center of the mold, apply a static pressure of 10-12MPa to the folded melt billet for 1-2min, and reheat to 190-220℃;

[0027] S3.3: Apply 5-10 MPa pressure to the melt billet that has been reheated to the mold temperature for 1-2 minutes, and repeat this step 2-4 times;

[0028] S3.4: Cool the mold for 15-20 minutes at a pressure of 20-25 MPa to obtain a polyethylene sheet.

[0029] Furthermore, the heating rate in step S3.1 is 5°C / min.

[0030] Furthermore, in step S3.1, the frequency of the pulse vibration field is 5 Hz and the amplitude is 15-20 MPa.

[0031] Furthermore, the adhesive in step S4 is JL-655PE plastic glue.

[0032] A polyethylene radiation-proof plate is prepared by the preparation process of the polyethylene radiation-proof plate.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects:

[0034] 1. The present invention modifies barite powder and makes it into a sandwich material to prepare a polyethylene radiation-proof sheet. Since barite has good absorption capacity for X-rays and gamma rays, adding barite when making the radiation-proof sheet can significantly improve the radiation protection performance of the sheet. In addition, barite can also be used as a filler for the interlayer of the sheet. Barite itself has a high density, and adding it to the sheet can effectively increase the density and physical properties of the sheet.

[0035] 2. The present invention modifies the barite powder by a coupling agent, thereby making the surface of the barite powder more active, having better dispersion performance, and not easy to agglomerate, which is convenient for subsequent combination with resin particles, so that the resin particles wrap the barite powder. The resin provides a good encapsulation and molding medium for the barite, so that the interlayer material prepared from the barite powder has the physical properties of qualified polyethylene sheets while providing radiation protection performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, further serve to explain the principles of the present disclosure and to enable those skilled in the relevant art to make and use the present disclosure.

[0037] Figure 1 The present invention is a flow chart of a process for preparing a polyethylene radiation-proof sheet material used in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following is a detailed description of a polyethylene radiation-proof sheet and its preparation process provided by the present invention in combination with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternative methods to implement some known technologies; and the accompanying drawings are only for a more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0039] Embodiment 1:

[0040] A preparation process of polyethylene radiation protection sheet, such as Figure 1 As shown, the following steps are included:

[0041] S1: Barite powder modification

[0042] S1.1: Weigh 95 parts by mass of barite powder and 5 parts by mass of coupling agent stearic acid, and add them dropwise while stirring the barite powder in a high-speed mixer;

[0043] S1.2: Then heat to 70°C and react for 10 minutes, discharge the material in the high-speed mixer, and obtain modified barite powder.

[0044] S2: Barite powder surface coated with resin to prepare interlayer material

[0045] S2.1: Add hexamethyldisiloxane, vinyl double-cap, deionized water, anhydrous ethanol and toluene into a reaction bottle, stir at a speed of 300 r / min, and simultaneously drop dilute hydrochloric acid, slowly raise the temperature to 50°C, and then drop 5% of the total volume of tetraethyl orthosilicate into the reaction bottle;

[0046] The volume ratio of hexamethyldisiloxane, vinyl double head, deionized water, anhydrous ethanol and toluene is 1:1:2:3:3.

[0047] S2.2: Then continue to raise the temperature to 70°C, react for 2h, and then cool to 50°C;

[0048] S2.3: Add toluene to the reaction flask for extraction for 2 hours, cool to room temperature, wash the obtained extract with water until neutral, dry with anhydrous calcium chloride, filter to remove salt, and remove the solvent by rotary evaporation to obtain a resin block;

[0049] S2.4: Crush the resin block and grind it through a 120-mesh sieve to obtain resin particles, mix the resin particles with modified barite powder and grind them to obtain a mixed powder, press the mixed powder into a mold at a pressure of 40 MPa and cure for 7 days to obtain a sandwich material, wherein the mass ratio of the resin particles to the modified barite powder is 2:1.

[0050] S3: Preparation of outer polyethylene sheet

[0051] S3.1: Pour polyethylene powder particles into a mold, and after being subjected to a pulse vibration force field for 3 minutes, heat the mixture to 190°C at a rate of 5°C / min to melt and form a well-welded melt blank. The frequency of the pulse vibration force field is 5 Hz and the amplitude is 15 MPa.

[0052] S3.2: The melt billet is taken out of the mold, and then the melt billet is quickly cut in half and folded, and the folded melt billet is placed back in the center of the mold, a static pressure of 10 MPa is applied to the folded melt billet for 2 minutes, and the temperature is raised to 190°C again;

[0053] S3.3: Apply a pressure of 5 MPa to the melt billet that has been reheated to the mold temperature for 2 minutes, and repeat this step 4 times;

[0054] S3.4: Cool the mold for 15 minutes at a pressure of 20 MPa to obtain a polyethylene sheet.

[0055] S4: Composite panel assembly

[0056] Two polyethylene sheets prepared in step S3 are adhered to the front and back sides of the sandwich material by an adhesive, and a pressure of 15 MPa is applied for 3 minutes to obtain a polyethylene radiation-proof sheet.

[0057] The adhesive is JL-655PE plastic glue.

[0058] Embodiment 2:

[0059] A preparation process of polyethylene radiation protection sheet, such as Figure 1 As shown, the following steps are included:

[0060] S1: Barite powder modification

[0061] S1.1: Weigh 100 parts by mass of barite powder and 10 parts by mass of coupling agent stearic acid, and add them dropwise while stirring the barite powder in a high-speed mixer;

[0062] S1.2: Then heat to 70°C and react for 10 minutes, discharge the material in the high-speed mixer, and obtain modified barite powder.

[0063] S2: Barite powder surface coated with resin to prepare interlayer material

[0064] S2.1: Add hexamethyldisiloxane, vinyl double-cap, deionized water, anhydrous ethanol and toluene into a reaction bottle, stir at a speed of 300 r / min, and simultaneously drop dilute hydrochloric acid, slowly raise the temperature to 50°C, and then drop 5% of the total volume of tetraethyl orthosilicate into the reaction bottle;

[0065] The volume ratio of hexamethyldisiloxane, vinyl double head, deionized water, anhydrous ethanol and toluene is 1:1:4:2:2.

[0066] S2.2: Then continue to raise the temperature to 70°C, react for 2h, and then cool to 50°C;

[0067] S2.3: Add toluene to the reaction flask for extraction for 2 hours, cool to room temperature, wash the obtained extract with water until neutral, dry with anhydrous calcium chloride, filter to remove salt, and remove the solvent by rotary evaporation to obtain a resin block;

[0068] S2.4: Crush the resin block and grind it through a 120-mesh sieve to obtain resin particles, mix the resin particles with modified barite powder and grind them to obtain a mixed powder, press the mixed powder into a mold at a pressure of 40 MPa and cure for 7 days to obtain a sandwich material, wherein the mass ratio of the resin particles to the modified barite powder is 3:1.

[0069] S3: Preparation of outer polyethylene sheet

[0070] S3.1: Pour polyethylene powder particles into a mold, and after being subjected to a pulse vibration force field for 3 minutes, heat the mixture to 190°C at a rate of 5°C / min to melt and form a well-welded melt blank. The frequency of the pulse vibration force field is 5 Hz and the amplitude is 15 MPa.

[0071] S3.2: The melt billet is taken out of the mold, and then the melt billet is quickly cut in half and folded, and the folded melt billet is placed back in the center of the mold, a static pressure of 10 MPa is applied to the folded melt billet for 2 minutes, and the temperature is raised to 190°C again;

[0072] S3.3: Apply a pressure of 5 MPa to the melt billet that has been reheated to the mold temperature for 2 minutes, and repeat this step 4 times;

[0073] S3.4: Cool the mold for 15 minutes at a pressure of 20 MPa to obtain a polyethylene sheet.

[0074] S4: Composite panel assembly

[0075] Two polyethylene sheets prepared in step S3 are adhered to the front and back sides of the sandwich material by an adhesive, and a pressure of 15 MPa is applied for 3 minutes to obtain a polyethylene radiation-proof sheet.

[0076] Embodiment 3:

[0077] A preparation process of polyethylene radiation protection sheet, such as Figure 1 As shown, the following steps are included:

[0078] S1: Barite powder modification

[0079] S1.1: Weigh 95 parts by mass of barite powder and 5 parts by mass of coupling agent stearic acid, and add them dropwise while stirring the barite powder in a high-speed mixer;

[0080] S1.2: Then heat to 75°C and react for 30 minutes, discharge the material in the high-speed mixer to obtain modified barite powder.

[0081] S2: Barite powder surface coated with resin to prepare interlayer material

[0082] S2.1: Add hexamethyldisiloxane, vinyl double-cap, deionized water, anhydrous ethanol and toluene into a reaction bottle, stir at a speed of 300 r / min, and simultaneously drop dilute hydrochloric acid, slowly raise the temperature to 50°C, and then drop 5% of the total volume of tetraethyl orthosilicate into the reaction bottle;

[0083] The volume ratio of hexamethyldisiloxane, vinyl double head, deionized water, anhydrous ethanol and toluene is 1:1:2:3:3.

[0084] S2.2: Then continue to raise the temperature to 75°C, react for 2.5h, and then cool to 50°C;

[0085] S2.3: Add toluene to the reaction flask for extraction for 2 hours, cool to room temperature, wash the obtained extract with water until neutral, dry with anhydrous calcium chloride, filter to remove salt, and remove the solvent by rotary evaporation to obtain a resin block;

[0086] S2.4: Crush the resin block and grind it through a 120-mesh sieve to obtain resin particles, mix the resin particles with modified barite powder and grind them to obtain a mixed powder, press the mixed powder into a mold at a pressure of 40 MPa and cure for 7 days to obtain a sandwich material, wherein the mass ratio of the resin particles to the modified barite powder is 2:1.

[0087] S3: Preparation of outer polyethylene sheet

[0088] S3.1: Pour polyethylene powder particles into a mold, and after being subjected to a pulse vibration force field for 3 minutes, heat the mold to 220°C at a rate of 5°C / min to melt and form a well-welded melt billet. The frequency of the pulse vibration force field is 5 Hz and the amplitude is 15 MPa.

[0089] S3.2: The melt billet is taken out of the mold, and then the melt billet is quickly cut in half and folded, and the folded melt billet is placed back in the center of the mold, a static pressure of 10 MPa is applied to the folded melt billet for 2 minutes, and the temperature is raised to 220°C again;

[0090] S3.3: Apply a pressure of 10 MPa to the melt billet that has been reheated to the mold temperature for 2 minutes, and repeat this step twice;

[0091] S3.4: Cool the mold for 20 minutes at a pressure of 25 MPa to obtain a polyethylene sheet.

[0092] S4: Composite panel assembly

[0093] Two polyethylene sheets prepared in step S3 are adhered to the front and back sides of the sandwich material by an adhesive, and a pressure of 20 MPa is applied for 3 minutes to obtain a polyethylene radiation-proof sheet.

[0094] The adhesive is JL-655PE plastic glue.

[0095] Comparative Example 1:

[0096] Compared with Example 1, Comparative Example 1 is a polyethylene sheet.

[0097] Comparative Example 2:

[0098] Compared with Example 1, the difference of Comparative Example 2 is that step S1 is not performed, and barite powder is directly added in step S2, specifically: "S2.1: hexamethyldisiloxane, vinyl double head, deionized water, anhydrous ethanol and toluene are added to a reaction bottle, stirred at a speed of 300 r / min, and dilute hydrochloric acid is added dropwise at the same time, the temperature is slowly raised to 50° C., and then 5% of the total volume of tetraethyl orthosilicate is added dropwise;

[0099] The volume ratio of hexamethyldisiloxane, vinyl double head, deionized water, anhydrous ethanol and toluene is 1:1:2:3:3.

[0100] S2.2: Then continue to raise the temperature to 70°C, react for 2h, and then cool to 50°C;

[0101] S2.3: Add toluene to the reaction flask for extraction for 2 hours, cool to room temperature, wash the obtained extract with water until neutral, dry with anhydrous calcium chloride, filter to remove salt, and remove the solvent by rotary evaporation to obtain a resin block;

[0102] S2.4: The resin block is crushed and ground through a 120-mesh sieve to obtain resin particles, the resin particles are mixed and ground with barite powder to obtain a mixed powder, the mixed powder is molded at a pressure of 40 MPa, and cured for 7 days to obtain a sandwich material, wherein the mass ratio of the resin particles to the modified barite powder is 2:1. The prepared polyethylene radiation protection sheet is recorded as Comparative Example 2.

[0103] Comparative Example 3:

[0104] Compared with Example 1, Comparative Example 3 is the outer layer polyethylene sheet prepared in step S3, and the three layers of outer layer polyethylene sheet are bonded together by the method of step S4, specifically: "The three layers of outer layer polyethylene sheet are bonded to the front and back sides of the sandwich material by an adhesive, and a pressure of 15 MPa is applied for 3 minutes to obtain a polyethylene radiation protection sheet, and the adhesive is JL-655PE plastic glue". The prepared polyethylene radiation protection sheet is recorded as Comparative Example 3.

[0105] The radiation protection performance test was carried out according to the national standard "GBZ / T147-2002 Determination of attenuation performance of X-ray protection materials", and the X-ray protection shielding test was carried out using standard X-rays (120KV, additional filtration of 2.50mmAl), as shown in Table 1.

[0106] Table 1

[0107] Thickness (mm) Lead equivalent value (mmPb) Example 1 10 1.17 Example 2 10 1.14 Example 3 10 1.12 Comparative Example 1 10 0.87 Comparative Example 2 10 0.62 Comparative Example 3 10 0.79

[0108] It can be seen that when the thickness is 10 mm, the lead equivalent value of Example 1 is 1.17 mmPb, that of Example 2 and Example 3 is 1.14 mmPb and 1.12 mmPb, while that of Comparative Example 1 is 0.87 mmPb. It can be seen that the polyethylene radiation protection plate prepared by the present invention has better radiation protection performance than commercially available products.

[0109] The lead equivalent value of Comparative Example 2 is 0.62 mmPb, and that of Comparative Example 3 is 0.79 mmPb. It can be seen that the radiation protection performance of the polyethylene sheet without resin wrapping and interlayer is much lower than that of Example 1, because the barite powder and resin provide the polyethylene sheet with radiation protection ability.

[0110] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A process for preparing a polyethylene radiation-proof sheet, characterized in that: The steps include: S1: Barite powder modification S1.1: Weigh 95-100 parts by weight of barite powder and 5-10 parts by weight of coupling agent stearic acid, and add them dropwise while stirring the barite powder in a high-speed mixer; S1.2: Then heat to 70-75℃ and react for 10-30min, discharge the material in the high-speed mixer to obtain modified barite powder; S2: Barite powder surface coated with resin to prepare interlayer material S2.1: Add hexamethyldisiloxane, vinyl double-capped end cap, deionized water, anhydrous ethanol and toluene into a reaction bottle, wherein the volume ratio of hexamethyldisiloxane, vinyl double-capped end cap, deionized water, anhydrous ethanol and toluene is 1:1:(2-4):(1-3):(2-3), stir at a speed of 300-350 r / min, and simultaneously dropwise add dilute hydrochloric acid, slowly raise the temperature to 50-55°C, and then dropwise add 1-5% of the total volume of tetraethyl orthosilicate; S2.2: Then continue to raise the temperature to 70-75°C, react for 2-2.5h, and then cool to 50°C; S2.3: Add toluene to the reaction flask for extraction for 2-2.5 hours, cool to room temperature, wash the obtained extract with water until neutral, dry with anhydrous calcium chloride, filter to remove salt, and remove the solvent by rotary evaporation to obtain a resin block; S2.4: crush the resin block and grind it through a 120-mesh sieve to obtain resin particles, mix the resin particles with modified barite powder and grind them evenly, the mass ratio of the resin particles to the modified barite powder is (2-3):1, to obtain a mixed powder, press the mixed powder into a mold at a pressure of 40 MPa, and cure for 7-8 days to obtain a sandwich material; S3: Preparation of outer polyethylene sheet S3.1: Pour polyethylene powder particles into the mold, and after being subjected to the pulse force field for 3-5 minutes, quickly heat up to 190-220°C to melt and form a well-welded melt blank; S3.2: Take the melt billet out of the mold, then quickly cut and fold the melt billet in half, and put the folded melt billet back into the center of the mold, apply a static pressure of 10-12MPa to the folded melt billet for 1-2min, and reheat to 190-220℃; S3.3: Apply 5-10 MPa pressure to the melt billet that has been reheated to the mold temperature for 1-2 minutes, and repeat this step 2-4 times; S3.4: Cool the mold for 15-20 minutes at a pressure of 20-25 MPa to obtain a polyethylene sheet; S4: Composite panel assembly The two polyethylene sheets prepared in step S3 are adhered to the front and back sides of the sandwich material by an adhesive, wherein the adhesive is JL-655PE plastic glue, and a pressure of 15-20 MPa is applied for 1-3 minutes to obtain a polyethylene radiation-proof sheet.

2. The process for preparing a polyethylene radiation-proof sheet material according to claim 1, characterized in that: The heating rate in step S3.1 is 5°C / min.

3. The preparation process of a polyethylene radiation-proof sheet material according to claim 1, characterized in that: In step S3.1, the frequency of the pulse vibration field is 5 Hz and the amplitude is 15-20 MPa.

4. A polyethylene radiation-proof sheet material, which is prepared by the preparation process of the polyethylene radiation-proof sheet material according to any one of claims 1 to 3.

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