1. A preparation method of an X-ray shielding composite material is characterized by comprising the following steps:

a) coating cyanoacrylate adhesive to form a cyanoacrylate film/sheet;

b) spraying X-ray shielding powder on the cyanoacrylate film/sheet to form a composite before the cyanoacrylate is cured;

c) after the cyanoacrylate in the compound is cured, crushing the compound to obtain cyanoacrylate-coated X-ray shielding particles;

d) blending and molding the cyanoacrylate-coated X-ray shielding particles and a base material to obtain an X-ray shielding composite material;

the base material is plastic or rubber.

2. The production method according to claim 1, wherein in the step b), the X-ray shielding powder is a metal powder and/or a compound powder of the metal;

the metal is selected from one or more of lead, bismuth, antimony, tungsten, tin, tantalum, barium and rare earth metal;

the metal compound is selected from one or more of metal oxide, metal hydroxide and metal sulfate compound.

3. The method according to claim 1 or 2, wherein the particle size of the X-ray shielding powder is 0.05 to 300 μm.

4. The method according to claim 1, wherein the sprayed density of the X-ray shielding powder on the cyanoacrylate film/sheet is 0.01 to 0.2g/cm²；

The thickness of the cyanoacrylate film/sheet is 0.06-0.8 mm.

5. The production method according to claim 1 or 4, wherein the mass ratio of the X-ray shielding powder in the X-ray shielding composite material is 10% to 90%;

the mass ratio of the cyanoacrylate-coated X-ray shielding particles in the X-ray shielding composite material is 15-95%.

6. The method according to claim 1, wherein in the step c), the particle size of the cyanoacrylate-coated X-ray shielding particles is 100 to 800 mesh.

7. The preparation method according to claim 1, wherein in the step d), the base material is selected from one or more of polyethylene, polypropylene, thermoplastic elastomer, polyurethane and modified polyvinyl chloride.

8. A method of manufacturing as claimed in claim 7, wherein the thermoplastic elastomer comprises a base material and a blend;

the base material is selected from one or more of SBS, SEBS and SEPS;

the blend is selected from one or more of polypropylene, naphthenic oil and paraffin oil;

the modified polyvinyl chloride is formed by the following materials in percentage by mass:

29.5 to 55 percent of polyvinyl chloride;

44.5 to 70 percent of plasticizer;

0.1 to 0.5 percent of heat stabilizer.

9. The preparation method according to claim 8, wherein the thermoplastic elastomer is formed from a material comprising the following components in mass ratio:

30-50% of matrix material;

2 to 10 percent of polypropylene;

40 to 60 percent of naphthenic oil or paraffinic oil.

10. An X-ray shielding composite material prepared by the preparation method of any one of claims 1 to 9.

Background

With the development of radiation research in the fields of medical imaging, interventional medicine, fluoroscopy, and the like, more and more X-ray devices are being applied to medical imaging, interventional surgery, and the like. But as people's understanding of X-rays is continuously expanded, awareness of harm to X-rays is gradually improved. In 2017, 10 and 27, the list of carcinogens published by the international cancer research institution of the world health organization is preliminarily collated for reference, and X-rays are listed as a list of carcinogens.

The main harm of X-ray to human body includes random effect and non-random effect, wherein the random effect is related to the dose threshold value of X-ray exposure, which may cause carcinogenesis, genetic effect, intrapartum irradiation effect, etc., thereby causing nausea, vomit, headache, abnormal hemogram, skin injury, leukemia, radiation cataract, skin cancer, and the basal ray during pregnancy may also cause fetal death, teratogenesis, serious mental retardation, etc. The nonrandom effect of X-rays can cause damage to blood and hematopoietic organ changes, ocular lens changes, radioactive skin damage, and the like. Therefore, it is necessary to shield and protect medical personnel and patients from scattered and unnecessary X-rays generated during the medical treatment.

At present, high atomic number metals or metal compounds such as lead, bismuth, antimony, tungsten, tantalum, rare earth and the like are mainly filled in rubber and plastic materials, and the X-ray shielding function is realized by utilizing the shielding effect of metal elements on X-rays and the flexibility of high polymer materials. However, because the compatibility between metal and non-metal high polymer is poor, the dispersion and distribution of metal or metal compound in plastic and rubber materials are not good, and the agglomeration of metal or metal compound is easy to occur, so that the prepared shielding material can not realize uniform shielding effect, and the thickness of the material must be increased or the addition amount of metal or metal compound must be increased to realize better shielding effect. Thereby leading to the defects of heavier and higher cost of the prior X-ray shielding material.

The existing X-ray shielding materials are generally prepared by mixing metal elements or metal compounds such as tungsten, bismuth, antimony, rare earth and the like into rubber and plastic materials. For example, CN107316667A is prepared by mixing tungsten powder, antimony powder and bismuth powder, stirring, adding into high molecular tough matrix, stirring, mixing, and tabletting. Although stirring can improve the dispersion of the metal powder in the material, the metal powder is easy to agglomerate in the later mixing and pressing process to form tablets, so that the dispersion and poor distribution phenomena occur, and the X-ray shielding effect is weakened.

In order to improve the dispersion and distribution of metal powder and metal compound, silane coupling agents are mostly adopted to modify the metal powder and the metal compound in the prior art. For example, CN101572129B uses silane coupling agent, and CN10781878A uses anionic dispersant and silane coupling agent. Silane coupling agents generally have a good coupling effect on materials such as silica and glass, but their effect in metals and their compounds is not very desirable.

In the prior art, a liquid coupling agent mode is adopted for pretreating metal and metal compound powder, and the coupling grafting of the coupling agent and the metal powder is realized by adopting a stirring mode and the like, but after most of metal, particularly metal powder of bismuth, antimony and the like is ground to a lower particle size, for example, the particle size is less than 100 mu m, the metal powder is easy to agglomerate due to the self characteristics of the metal, the metal powder cannot be effectively separated by stirring, and the metal powder with the lower particle size cannot be obtained by stirring.

Therefore, how to improve the shielding effect and performance of the X-ray shielding material and reduce the material cost becomes a problem to be solved urgently.

Disclosure of Invention

In view of the above, the present invention is directed to an X-ray shielding composite material and a method for preparing the same. The X-ray shielding composite material provided by the invention can effectively realize X-ray shielding, improve the mechanical property and reduce the cost.

The invention provides a preparation method of an X-ray shielding composite material, which comprises the following steps:

a) coating cyanoacrylate adhesive to form a cyanoacrylate film/sheet;

b) spraying X-ray shielding powder on the cyanoacrylate film/sheet to form a composite before the cyanoacrylate is cured;

c) after the cyanoacrylate in the compound is cured, crushing the compound to obtain cyanoacrylate-coated X-ray shielding particles;

d) blending and molding the cyanoacrylate-coated X-ray shielding particles and a base material to obtain an X-ray shielding composite material;

the base material is plastic or rubber.

Preferably, in the step b), the X-ray shielding powder is a metal powder and/or a compound powder of the metal;

the metal is selected from one or more of lead, bismuth, antimony, tungsten, tin, tantalum, barium and rare earth metal;

the metal compound is selected from one or more of metal oxide, metal hydroxide and metal sulfate compound.

Preferably, the particle size of the X-ray shielding powder is 0.05 to 300 μm.

Preferably, the spraying density of the X-ray shielding powder on the cyanoacrylate film/sheet is 0.01-0.2 g/cm²；

The thickness of the cyanoacrylate film/sheet is 0.06-0.8 mm.

Preferably, the mass ratio of the X-ray shielding powder in the X-ray shielding composite material is 10-90%;

the mass ratio of the cyanoacrylate-coated X-ray shielding particles in the X-ray shielding composite material is 15-95%.

Preferably, in the step c), the particle size of the cyanoacrylate-coated X-ray shielding particles is 100-800 meshes.

Preferably, in the step d), the base material is selected from one or more of polyethylene, polypropylene, thermoplastic elastomer, polyurethane and modified polyvinyl chloride.

Preferably, the thermoplastic elastomer comprises a matrix material and a blend;

the base material is selected from one or more of SBS, SEBS and SEPS;

the blend is selected from one or more of polypropylene, naphthenic oil and paraffin oil;

the modified polyvinyl chloride is formed by the following materials in percentage by mass:

29.5 to 55 percent of polyvinyl chloride;

44.5 to 70 percent of plasticizer;

0.1 to 0.5 percent of heat stabilizer.

Preferably, the thermoplastic elastomer is formed by materials comprising the following components in percentage by mass:

30-50% of matrix material;

2 to 10 percent of polypropylene;

40 to 60 percent of naphthenic oil or paraffinic oil.

The invention also provides the X-ray shielding composite material prepared by the preparation method in the technical scheme.

Coating a specific cyanoacrylate adhesive to form a film/sheet, spraying X-ray shielding material powder on the surface of the film/sheet before curing the film/sheet, and crushing an integral compound after the adhesive is cured to obtain dispersed and well-distributed coating filler, namely cyanoacrylate-coated X-ray shielding material particles; the X-ray shielding composite material is blended and molded with a base material to obtain the X-ray shielding composite material, so that the dispersion of particles of a coated X-ray shielding material in the base material is improved, the agglomeration of the X-ray shielding material, particularly when the particle size is small, is effectively controlled, the performance of the obtained X-ray shielding composite material is uniform and stable, the X-ray shielding can be effectively realized by the material under the condition of lower thickness, and compared with the prior art, the material thickness is greatly reduced, so that the cost is reduced; meanwhile, the cyanoacrylate adhesive has strong bonding force with metal and good compatibility with a high polymer base material, can greatly improve the bonding force of a metal/metal compound shielding material and the high polymer, and effectively improves the mechanical property of the material.

Test results show that the X-ray shielding composite material provided by the invention can realize that the thickness of a sheet required by X-ray shielding (0.25mm lead equivalent) is less than 0.90mm, shows a better X-ray shielding effect and greatly reduces the cost; meanwhile, the tensile property of the composite material is obviously improved.

Detailed Description

The invention provides a preparation method of an X-ray shielding composite material, which comprises the following steps:

a) coating cyanoacrylate adhesive to form a cyanoacrylate film/sheet;

b) spraying X-ray shielding powder on the cyanoacrylate film/sheet to form a composite before the cyanoacrylate is cured;

c) after the cyanoacrylate in the compound is cured, crushing the compound to obtain cyanoacrylate-coated X-ray shielding particles;

d) blending and molding the cyanoacrylate-coated X-ray shielding particles and a base material to obtain an X-ray shielding composite material;

the base material is plastic or rubber.

According to the present invention, cyanoacrylate adhesive is applied to form cyanoacrylate films/sheets.

In the invention, the cyanoacrylate adhesive is also called 502 adhesive, and the applicant researches and discovers that cyanoacrylate has stronger binding force with metal and combines the characteristic of quick curing of the cyanoacrylate, and the cyanoacrylate is used as a dispersant of metal/metal compounds to realize quick and effective dispersion of the metal/metal compounds; meanwhile, the characteristic that cyanoacrylate is brittle is utilized, and the conventional method can be adopted for crushing and scattering after dispersion, so that the subsequent filling in the high polymer base material is facilitated. Meanwhile, the cyanoacrylate has good compatibility with the high polymer, and the bonding force of the metal/metal compound and the high polymer base material can be greatly improved after the crushed material is filled, so that the mechanical property of the composite material is obviously improved.

In the present invention, the coating method is not particularly limited, and may be a coating method known to those skilled in the art, such as painting or knife coating. After coating treatment, cyanoacrylate film/sheet is formed. In the invention, the coating is carried out on a substrate, wherein the substrate is preferably a substrate which is not adhered with cyanoacrylate, so that the subsequent stripping of the cyanoacrylate adhesive film/sheet is convenient; in some embodiments of the invention, the substrate is a polytetrafluoroethylene substrate. In some embodiments of the invention, the cyanoacrylate adhesive is uniformly coated onto the polytetrafluoroethylene roller through an oblong die, causing the roller to rotate at a constant speed, and the cyanoacrylate film/sheet can be taken up on the other side of the roller due to the faster curing of the cyanoacrylate and the non-adhesion to the polytetrafluoroethylene.

According to the present invention, after the cyanoacrylate film/sheet is formed, before it is cured, X-ray shielding powder is sprayed onto the cyanoacrylate film/sheet to form a composite.

In the invention, cyanoacrylate can be cured after a certain time, and before the cyanoacrylate is cured, X-ray shielding powder is sprayed on the surface of the cyanoacrylate so that the cyanoacrylate is fully contacted with the X-ray shielding powder.

In the present invention, the X-ray shielding powder is a metal powder and/or a compound powder of the metal. Wherein, the metal is preferably one or more of lead, bismuth, antimony, tungsten, tin, tantalum, barium and rare earth metal. The compound of the metal is preferably one or more of a metal oxide, a metal hydroxide and a metal sulfate compound.

In the present invention, the particle size of the X-ray shielding powder is preferably 0.05 to 300. mu.m, and more preferably 40 to 300. mu.m. The particle size of the X-ray shielding material powder can be controlled by ball milling, namely, the X-ray shielding material is ball milled in advance before spraying, and then spraying is carried out after the powder with the specific particle size is obtained; when two or more than two kinds of X-ray shielding material powders are used, a plurality of kinds of X-ray shielding materials can be ball-milled in the same ball mill, and it is preferable to simultaneously spray the powders by using a plurality of ball mills and a plurality of spray heads in order to prevent uneven spraying due to different densities of the metal powders.

In the present invention, after the powder of the X-ray shielding material is ball-milled and pulverized, it is preferably blown out by a strong blowing method to prevent the agglomeration of the X-ray shielding material powder having a relatively low particle size. In the present invention, it is preferable to obtain the powder having a relatively large particle diameter by filtering the powder with a sieve having a predetermined mesh number at the discharge end. After ball milling, the grain diameter of most of the powder meets the requirement, only a small amount of unqualified powder is filtered, and the unqualified powder accounts for less than 10 percent of the total powder by mass. The invention can move the spray head or the cyanoacrylate position at a constant speed to realize uniform distribution while spraying.

In the present invention, the spraying is carried out on one surface of the cyanoacrylate film/sheet, that is, on a surface not in contact with the substrate for coating. The spraying method is not particularly limited, and may be, for example, spraying, dusting, or the like, and the X-ray shielding powder may be uniformly sprayed. After spraying, the X-ray shielding powder is uniformly dispersed on the cyanoacrylate film/sheet to obtain the compound.

In the invention, in the finally obtained composite material, the mass ratio of the X-ray shielding powder to the whole composite material is 10-90%, preferably 60-90%. In some embodiments of the invention, the X-ray shielding powder is lead powder, bismuth powder, or antimony powder.

When a cyanoacrylate film/sheet is formed in the first step and X-ray shielding powder is sprayed in the second step, the uniformity and the stability of the material are improved in an auxiliary mode by controlling the thickness of the cyanoacrylate film/sheet and the spraying density of the X-ray shielding powder; in the invention, the thickness of the cyanoacrylate film/sheet is preferably 0.06-0.8 mm, and more preferably 0.08-0.3 mm; the spraying density of the X-ray shielding powder on the cyanoacrylate film/sheet is preferably 0.01-0.2 g/cm²More preferably 0.03 to 0.1g/cm²。

In the invention, in order to realize uniform spraying, the cyanoacrylate adhesive can be uniformly coated on a substrate roller through a flat and long mouth mold, the roller rotates at a uniform speed, X-ray shielding powder is sprayed on the surface of the roller in the rotating process, and the X-ray shielding powder can be sprayed on a cyanoacrylate film/sheet rotating at a uniform speed by utilizing high-speed compressed air flow in the spraying process. Because the cyanoacrylate adhesive is cured faster, the spraying position is preferably controlled at one end close to the die, and after spraying, the film/sheet collected at the other side of the substrate roll is cyanoacrylate coated with X-ray shielding powder.

According to the invention, after spraying the compound, after the cyanoacrylate in the compound is solidified, crushing is carried out to obtain cyanoacrylate-coated X-ray shielding particles.

In the invention, the condition for curing the cyanoacrylate is not particularly limited, and the curing can be carried out at room temperature, and the curing time is generally 0.1-2 min under the thickness. After curing, the composite is subjected to a pulverization treatment. The mode of the pulverization treatment is not particularly limited in the present invention, and may be a material pulverization mode known to those skilled in the art, and the pulverization treatment is preferably performed by using a pulverizer or a ball mill in the present invention. The particle size of cyanoacrylate-coated X-ray shielding particles is preferably controlled to be 100-800 meshes. The required particle size can be obtained by controlling the crushing speed, time and ball milling ball size; in the invention, in order to obtain the particle size, the ball milling speed is preferably 100-500 rpm, and the time is preferably 5-24 h; the grinding ball is preferably a zirconia grinding ball, and the ratio of the grinding balls with the diameters of phi 1mm-5mm, phi 10-15mm and phi 20-25mm is 3: 5: 2. In the invention, after the ball milling and crushing, the X-ray shielding material particles which are not coated are filtered by adopting a vibration or blowing mode, and the cyanoacrylate-coated X-ray shielding material particles are obtained.

According to the invention, after the cyanoacrylate-coated X-ray shielding material particles are obtained, the cyanoacrylate-coated X-ray shielding material particles are mixed with the base material and formed, and the X-ray shielding composite material is obtained.

In the invention, the base material is plastic or rubber; preferably one or more of Polyethylene (PE), polypropylene (PP), thermoplastic elastomer (TPR), polyurethane (TPU) and modified polyvinyl chloride.

Wherein the thermoplastic elastomer comprises a matrix material and a blend material. The base material is preferably one or more of SBS (styrene-butadiene-styrene copolymer), SEBS (hydrogenated styrene-butadiene-styrene copolymer) and SEPS (hydrogenated styrene-pentadiene-styrene copolymer). The blend is preferably one or more of polypropylene, naphthenic oil and paraffinic oil.

In some embodiments of the present invention, the thermoplastic elastomer is formed from a material comprising the following components in mass ratio:

30-50% of matrix material;

2 to 10 percent of polypropylene;

40 to 60 percent of naphthenic oil or paraffinic oil.

Wherein, the modified polyvinyl chloride is preferably formed by materials comprising the following components in percentage by mass:

29.5 to 55 percent of polyvinyl chloride;

44.5 to 70 percent of plasticizer;

0.1 to 0.5 percent of heat stabilizer.

The plasticizer preferably comprises one or more of dibutyl phthalate and dioctyl phthalate. The heat stabilizer preferably comprises one or more of zinc stearate and calcium stearate.

In the present invention, the blending mode is not particularly limited, and is a conventional mixing mode well known to those skilled in the art, and the present invention may be cooperatively performed by one or more of single screw, twin screw, open mill and internal mixing. In the present invention, the molding manner is not particularly limited, and may be a conventional molding manner known to those skilled in the art, and the X-ray shielding composite material may be obtained by screw extrusion molding or injection molding. Wherein the mass ratio of the cyanoacrylate-coated X-ray shielding particles in the X-ray shielding composite material is preferably 15% to 95%.

The invention also provides the X-ray shielding composite material prepared by the preparation method in the technical scheme. The X-ray shielding composite material provided by the invention has uniform and stable performance, the whole material can uniformly and effectively realize X-ray shielding, the molding material can realize X-ray shielding under a thinner thickness, the material cost is reduced, and the mechanical property of the material is better.

The X-ray shielding composite material provided by the invention can be applied to medical materials such as infusion apparatus catheters, infusion extension tubes, radiography needle copper infusion extension tubes and the like.

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

Example 1

1.1 materials

Base material: modified polyvinyl chloride

X-ray shielding:

545.55 parts by mass of lead powder (84.47% of the total mass of the base material and the lead powder).

1.2 preparation

S1, uniformly coating the cyanoacrylate adhesive on a polytetrafluoroethylene roller (the coating thickness is 0.1mm) through a flat and long die, ensuring that the roller rotates at a constant speed, and forming a cyanoacrylate film on the roller.

S2, ball-milling the lead powder in a ball mill (the ball-milling particle size is 50 mu m), introducing high-speed compressed air flow, and blowing the metal powder to the surface of the cyanoacrylate film (the spraying density is 0.05 g/cm)²) The spray position was close to one end of the die, and the cyanoacrylate film coated with the metal powder was taken up on the other side of the roll.

S3, crushing the film, filtering out cyanoacrylate powder without coating metal powder by gas purging after crushing, and then sieving to screen out cyanoacrylate coating metal powder with the particle size of 300 meshes, wherein the total amount is 600 parts by mass (the accounting ratio in the whole composite material is 85.68%).

S4, adding PVC, zinc stearate and calcium stearate into a high-speed mixer, and stirring at the rotating speed of 800rpm for 3 min; then adding dioctyl phthalate, and stirring at high speed of 2000rpm for 5min to obtain the base material. After the temperature of the base material is reduced to room temperature, cyanoacrylate-coated metal powder is added, high-speed stirring is carried out, the rotating speed is 1500rpm, and discharging is carried out after 3 min.

And S5, forming the obtained material by a double-screw sheet extruder to obtain the X-ray shielding composite material sheet.

Example 2

1.1 materials

Base material: modified polyvinyl chloride

X-ray shielding:

545.55 parts by mass of lead powder (84.47% of the total mass of the base material and the lead powder).

1.2 preparation

S1, uniformly coating the cyanoacrylate adhesive on a polytetrafluoroethylene roller (the coating thickness is 0.1mm) through a flat and long die, ensuring that the roller rotates at a constant speed, and forming a cyanoacrylate film on the roller.

S2, ball-milling the lead powder in a ball mill (the ball-milling particle size is 50 mu m), introducing high-speed compressed air flow, and blowing the metal powder to the surface of the cyanoacrylate film (the spraying density is 0.05 g/cm)²) The spray position was close to one end of the die, and the cyanoacrylate film coated with the metal powder was taken up on the other side of the roll.

S3, crushing the film, filtering out cyanoacrylate powder without coating metal powder by gas purging after crushing, and then sieving to screen out cyanoacrylate coating metal powder with the particle size of 300 meshes, wherein the total amount is 600 parts by mass (the accounting ratio in the whole composite material is 85.68%).

S4, adding PVC, zinc stearate and calcium stearate into a high-speed mixer, and stirring at the rotating speed of 800rpm for 3 min; then adding dioctyl phthalate, and stirring at high speed of 2000rpm for 5min to obtain the base material. After the temperature of the base material is reduced to room temperature, cyanoacrylate-coated metal powder is added, high-speed stirring is carried out, the rotating speed is 1500rpm, and discharging is carried out after 3 min.

And S5, forming the obtained material by a double-screw sheet extruder to obtain the X-ray shielding composite material sheet.

Example 3

1.1 materials

Base material: modified polyvinyl chloride

X-ray shielding:

545.55 parts by mass of bismuth powder (84.47% of the total mass of the base material and the bismuth powder).

1.2 preparation

S1, uniformly coating the cyanoacrylate adhesive on a polytetrafluoroethylene roller (the coating thickness is 0.1mm) through a flat and long die, ensuring that the roller rotates at a constant speed, and forming a cyanoacrylate film on the roller.

S2, ball-milling the bismuth powder in a ball mill (the ball-milling particle size is 50 mu m), introducing high-speed compressed air flow, and blowing the metal powder to the surface of the cyanoacrylate film (the spraying density is 0.05 g/cm)²) The spray position was close to one end of the die, and the cyanoacrylate film coated with the metal powder was taken up on the other side of the roll.

S3, crushing the film, filtering out cyanoacrylate powder without coating metal powder by gas purging after crushing, and then sieving to screen out cyanoacrylate coating metal powder with the particle size of 300 meshes, wherein the total amount is 600 parts by mass (the accounting ratio in the whole composite material is 85.68%).

S4, adding PVC, zinc stearate and calcium stearate into a high-speed mixer, and stirring at the rotating speed of 800rpm for 3 min; then adding dioctyl phthalate, and stirring at high speed of 2000rpm for 5min to obtain the base material. After the temperature of the base material is reduced to room temperature, cyanoacrylate-coated metal powder is added, high-speed stirring is carried out, the rotating speed is 1500rpm, and discharging is carried out after 3 min.

And S5, forming the obtained material by a double-screw sheet extruder to obtain the X-ray shielding composite material sheet.

Example 4

1.1 materials

Base material: modified polyvinyl chloride

X-ray shielding:

545.55 parts by mass of antimony powder (84.47% of the total mass of the base material and the antimony powder).

1.2 preparation

S1, uniformly coating the cyanoacrylate adhesive on a polytetrafluoroethylene roller (the coating thickness is 0.1mm) through a flat and long die, ensuring that the roller rotates at a constant speed, and forming a cyanoacrylate film on the roller.

S2, ball-milling antimony powder in a ball mill (the ball-milling particle size is 50 mu m), introducing high-speed compressed air flow, and blowing and spraying metal powder to the surface of the cyanoacrylate film (the spraying density is 0.05 g/cm)²) The spray position was close to one end of the die, and the cyanoacrylate film coated with the metal powder was taken up on the other side of the roll.

S3, crushing the film, filtering out cyanoacrylate powder without coating metal powder by gas purging after crushing, and then sieving to screen out cyanoacrylate coating metal powder with the particle size of 300 meshes, wherein the total amount is 600 parts by mass (the accounting ratio in the whole composite material is 85.68%).

S4, adding PVC, zinc stearate and calcium stearate into a high-speed mixer, and stirring at the rotating speed of 800rpm for 3 min; then adding dioctyl phthalate, and stirring at high speed of 2000rpm for 5min to obtain the base material. After the temperature of the base material is reduced to room temperature, cyanoacrylate-coated metal powder is added, high-speed stirring is carried out, the rotating speed is 1500rpm, and discharging is carried out after 3 min.

And S5, forming the obtained material by a double-screw sheet extruder to obtain the X-ray shielding composite material sheet.

Example 5

1.1 materials

Base material: SEBS

30 parts by mass of SEBS (30%);

10 parts by mass (10%) of polypropylene;

60 parts by mass (60%) of paraffin oil;

x-ray shielding:

545.55 parts by mass of antimony powder (84.51% of the total mass of the base material and the antimony powder).

1.2 preparation

S1, uniformly coating the cyanoacrylate adhesive on a polytetrafluoroethylene roller (the coating thickness is 0.1mm) through a flat and long die, ensuring that the roller rotates at a constant speed, and forming a cyanoacrylate film on the roller.

S2, ball-milling antimony powder in a ball mill (the ball-milling particle size is 50 mu m), introducing high-speed compressed air flow, and blowing and spraying metal powder to the surface of the cyanoacrylate film (the spraying density is 0.05 g/cm)²) The spray position was close to one end of the die, and the cyanoacrylate film coated with the metal powder was taken up on the other side of the roll.

S3, crushing the film, filtering out cyanoacrylate powder without coating metal powder by gas purging after crushing, and then sieving to screen out cyanoacrylate coating metal powder with the particle size of 300 meshes, wherein the total amount is 600 parts by mass (the accounting ratio in the whole composite material is 85.71%).

And S4, adding the SEBS into a high-speed mixer, stirring at the rotating speed of 2000rpm, adding the paraffin oil, and continuing stirring for 5min to obtain the base material. After the temperature of the base material is reduced to room temperature, cyanoacrylate-coated metal powder is added, high-speed stirring is carried out, the rotating speed is 1500rpm, and discharging is carried out after 3 min.

And S5, forming the obtained material by a double-screw sheet extruder to obtain the X-ray shielding composite material sheet.

Comparative example 1

1.1 materials

Base material: modified polyvinyl chloride

X-ray shielding:

the mass ratio of the lead powder to the base material is 84.47%.

1.2 preparation

And S1, ball-milling the lead powder in a ball mill (the ball-milling particle size is 50 mu m) to obtain the metal powder.

S2, adding PVC, zinc stearate and calcium stearate into a high-speed mixer, and stirring at the rotating speed of 800rpm for 5 min; then adding dioctyl phthalate, and stirring at low speed of 2000rpm for 3min to obtain the base material. And (3) after the temperature of the base material is reduced to room temperature, adding metal powder, stirring at a high speed of 1500rpm for 3min, and discharging.

And S3, forming the obtained material by a double-screw sheet extruder to obtain the X-ray shielding composite sheet.

Example 6

The composite sheets obtained in examples 1 to 5 and comparative example 1 were subjected to performance tests, and the results are shown in table 1. The sheet thickness is the minimum sheet thickness required to prevent direct and scattered X-rays corresponding to a lead equivalent of 0.25mm under a tube voltage of 100 KV.

TABLE 1 Properties of composites of examples 1-5 and comparative example 1

	Tensile strength, Mpa	Elongation at break,%	Hardness, Shore A	Thickness of sheet, mm
					Example 1	3.0	149	85	0.75
Example 2	2.7	397	82	0.72
					Example 3	2.1	246	90	0.90
Example 4	2.3	270	84	0.85
					Example 5	3.3	180	81	0.86
Comparative example 1	1.7	59	90	1.1

As can be seen from the test results in Table 1, compared with comparative example 1, the thickness of the sheet material of examples 1 to 5 of the present invention is significantly reduced, i.e., the thickness of the material required for X-ray shielding can be significantly reduced, thereby reducing the material cost and avoiding the inconvenience in use due to the heavy material. Meanwhile, compared with the comparative example 1, the mechanical properties of the examples 1 to 5 are also obviously improved.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.