Ultrahigh molecular weight polyethylene film and laminated part product thereof

Abstract

The invention relates to an ultra-high molecular weight polyethylene film, the viscosity average molecular weight of ultra-high molecular weight polyethylene is greater than 500,000, the density D of the film is greater than 0.80 g.cm <-3 >, and the elastic modulus M is greater than 120GPa. The ultra-high molecular weight polyethylene film is characterized in that the elastic modulus and the density of the ultra-high molecular weight polyethylene film meet the following relational expression: Mgt; the total draft multiple of the ultra-high molecular weight polyethylene film in one direction is at least 25 times.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to an ultra-high molecular weight polyethylene film with high impact resistance and its laminated product, which is especially suitable for the protection field requiring extremely high impact resistance. Background Art

[0002] Ultra-high molecular weight polyethylene (UHMWPE) film with high impact resistance is a polymer material with excellent mechanical properties such as high strength, high modulus, and low density, and is widely used in the manufacture of protective equipment such as bulletproof vests and bulletproof helmets. UHMWPE generally refers to polyethylene with a molecular weight between 1.5 million and 10 million. Due to its long molecular chains and relatively high entanglement density between molecular chains, the melt viscosity after melting is relatively large, making it difficult to directly process and form by conventional melt extrusion processes. In the existing disclosed methods, UHMWPE films (uniaxially or biaxially stretched) usually use the gel method (such as patent CN113263747B) or the low-temperature solid pressing method (such as patent CN102066073A) to prepare the base film, and then prepare UHMWPE films with different properties and uses through thermal drawing by a certain multiple. Among them, the former requires a large amount of solvent and the preparation process is relatively complex, while the latter requires UHMWPE powder with a special structure and has high requirements for the performance of raw materials. It is difficult to balance the impact resistance and processability of ultra-high molecular weight polyethylene films.

[0003] Patent CN101795848A discloses a polyethylene film with high tensile strength and high breaking energy. This film uses UHMWPE with a molecular weight of more than 500,000 as the raw material, and through low-temperature pressing and stretching steps, an ultra-high molecular weight polyethylene stretched film with high tensile strength and breaking energy is prepared. Patent CN111542427B discloses a polyethylene sheet made of UHMWPE with a viscosity-average molecular weight of more than 2 million. When the width is greater than 10.0 mm and the modulus is at least 100 N / tex, the loss factor is tested by DMA, and it is found that it has higher impact resistance when meeting a certain inequality.

[0004] In summary, in the existing disclosed processes related to UHMWPE films / strips / sheets, etc., the adjustment of their impact resistance mostly relies on simple adjustment of single properties such as strength, modulus, breaking energy, and density, lacking precise control over the relationship between the defect degree inside the film, the regularity of molecular chain arrangement, and the elastic modulus and other factors on the impact resistance of the film. Therefore, there is an urgent need to provide a scheme for regulating the density and elastic modulus of ultra-high molecular weight polyethylene films to prepare protective materials with higher impact resistance.

[0005] Based on this, the present invention studies the mutual relationship among the width-to-thickness ratio, density, and molecular chain arrangement regularity of ultra-high molecular weight polyethylene films and their influence on the impact resistance performance, and further provides a precise control method for elastic modulus and density, thereby improving the impact resistance performance of laminates prepared from ultra-high molecular weight polyethylene films. Summary of the Invention

[0006] The present invention relates to an ultra-high molecular weight polyethylene film and its laminate products. The elastic modulus and density of the film satisfy a certain relationship, and the impact resistance performance of the laminate products prepared from this film is significantly improved.

[0007] The applicant explains that ultra-high molecular weight polyethylene films (referred to as films in the present invention) also include ultra-high molecular weight polyethylene strips or ultra-high molecular weight polyethylene sheets.

[0008] The technical solution of the present invention is as follows:

[0009] An ultra-high molecular weight polyethylene film, wherein the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is greater than 500,000. Among them, the film density D is greater than 0.80 g / cm -3 , and the elastic modulus M is greater than 120 GPa. Its characteristics are: the elastic modulus and density of the ultra-high molecular weight polyethylene film satisfy the following relationship: M > 141D + 7, where the total draw ratio of the ultra-high molecular weight polyethylene film in one direction is at least 25 times.

[0010] Further, the ultra-high molecular weight polyethylene film of the present invention is prepared by subjecting polyethylene powder with a molecular weight of more than 500,000 to low-temperature solid pressing or making it into a gel film and then extracting and drying, to prepare an ultra-high molecular weight polyethylene base film, and then preparing it through a high-draw ratio process.

[0011] The ultra-high molecular weight polyethylene film is formed by multi-fold drawing of the ultra-high molecular weight polyethylene base film in one direction. During the drawing process, the drawing temperature and the total draw ratio have an important impact on the performance of the prepared film. The drawing temperature affects the density of the film. Under the condition of a certain draw ratio, the higher the drawing temperature, the higher the density. However, after the drawing temperature reaches a certain level, due to the enhanced molecular chain mobility and the increasing tendency of disorientation, the elastic modulus of the film may be reduced to a certain extent; the total draw ratio affects the width and elastic modulus of the film. The larger the total draw ratio, the smaller the width, and under the condition that the density does not decrease significantly, the greater the elastic modulus.

[0012] Further, the drawing temperature of the ultra-high molecular weight polyethylene film of the present invention is 135 - 165 °C, preferably 138 - 162 °C, and more preferably 140 - 160 °C.

[0013] Furthermore, the total draw ratio of the ultra-high molecular weight polyethylene film of the present invention in one direction is at least 25 times, preferably greater than 30 times, more preferably greater than 35 times.

[0014] When the drawing temperature of the ultra-high molecular weight polyethylene film of the present invention is 135 - 165 °C, the higher the total draw ratio, the higher the elastic modulus of the resulting film.

[0015] Furthermore, the elastic modulus M of the ultra-high molecular weight polyethylene film satisfies M≥120 GPa, preferably M≥130 GPa, more preferably M≥140 GPa, still more preferably ≥145 GPa, and most preferably ≥150 GPa.

[0016] Furthermore, the density D of the ultra-high molecular weight polyethylene film satisfies D≥0.80 g / cm -3 , preferably ≥0.85 g / cm -3 , more preferably ≥0.88 g / cm -3 , still more preferably ≥0.90 g / cm -3 , most preferably ≥0.92 g / cm -3 .

[0017] The theoretical density of the ultra-high molecular weight polyethylene film is 0.97 g / cm -3 , and the closer the density of the resulting film is to the theoretical density, the fewer the defects in the film and the higher the elastic modulus of the film. During the production of the ultra-high molecular weight polyethylene film, the methods to reduce density reduction can be specifically: optimizing the stretching process conditions to better match parameters such as temperature, speed, and draw ratio; precisely controlling the tension during stretching to ensure uniform distribution and avoid the formation of defects and density reduction caused by over-stretching due to excessive local tension; performing post-treatment heat treatment on the film to eliminate local internal stress and close some micro-defects, thereby further increasing the film density, etc.

[0018] Furthermore, the thickness T of the ultra-high molecular weight polyethylene film satisfies T≥10 μm, preferably ≥15 μm, more preferably ≥18 μm, still more preferably ≥20 μm, and most preferably ≥22 μm.

[0019] Furthermore, the width W of the ultra-high molecular weight polyethylene film satisfies W≥300 mm, preferably ≥350 mm, more preferably ≥400 mm, still more preferably ≥450 mm, and most preferably ≥500 mm.

[0020] Furthermore, the aspect ratio (i.e., the ratio of width W to thickness T) of the ultra-high molecular weight polyethylene film satisfies ≥10000, preferably ≥20000, more preferably ≥25000, still more preferably ≥30000, and most preferably ≥35000.

[0021] When the thickness of the ultra-high molecular weight polyethylene film is determined, the larger the width-to-thickness ratio, the wider the film, and it can be directly used for the preparation of impact-resistant products without splicing, effectively reducing the reduction or even damage of the product performance caused by stress concentration at the splicing gap, and improving the stability and consistency of the product to a certain extent.

[0022] Further, the crystallinity of the ultra-high molecular weight polyethylene film is ≥75%, preferably ≥80%, more preferably ≥85%, still more preferably ≥88%, and most preferably ≥90%.

[0023] Further, the orientation degree of the ultra-high molecular weight polyethylene film is ≥90%, preferably ≥95%, more preferably ≥98%, still more preferably ≥98.5%, and most preferably ≥99%.

[0024] Generally, orientation can induce crystallization, and the crystallinity will be higher when the orientation degree is high.

[0025] Since the glass transition temperature of polyethylene is relatively low (below -80°C), and the molecular chain has no branches, the resistance to the movement of the molecular chain is relatively small, and the oriented molecular chain is extremely easy to relax. Crystallization can fix the structure of the oriented molecular chain and make it stably exist at a certain temperature. The higher the crystallinity, the more stable the condensed state structure of the molecular chain in the UHMWPE film, and the more stable the performance during subsequent use. The higher the orientation degree of the UHMWPE film, the more regular the arrangement of the molecular chain, and the faster the impact energy propagates and dissipates inside it (the propagation speed of the shock wave along the molecular chain direction is faster). When used as an impact-resistant product, its impact resistance is better.

[0026] The present invention also provides a laminated product made of the above-mentioned ultra-high molecular weight polyethylene film.

[0027] The laminated product comprises a plurality of films as described in claim 1, and each single layer is composed of one film or prepared by splicing a plurality of films. Among them, the maximum orientation direction of each single layer is different from that of the next single layer.

[0028] As described herein, the ultra-high molecular weight polyethylene film laminated product according to the present invention can be prepared by the following process:

[0029] 1) Lay a single layer obtained by cutting and / or splicing a plurality of ultra-high molecular weight polyethylene films to form a material to be pressed, place it in a lamination mold, and close the mold.

[0030] 2) Perform primary hot pressing on the plurality of single layers prepared in step 1) to form a preform.

[0031] 3) Perform secondary hot pressing on the preform prepared in step 2).

[0032] 4) Cool the mold and open the mold to take out the laminated product.

[0033] Among the multiple single layers of ultra-high molecular weight polyethylene films in step 1), the maximum orientation direction of each single layer is different from that of the next single layer; each single layer has the same size.

[0034] Furthermore, when the material to be pressed in step 1) is placed in the mold, it is wrapped with release paper on both the top and bottom.

[0035] The time for the first hot pressing in step 2) is 15 - 30 minutes; the temperature is 115 - 130 °C, and the pressure is 2.0 - 12 MPa.

[0036] The time for the second hot pressing in step 3) is 30 - 40 minutes; the temperature is 125 - 135 °C, and the pressure is 22.0 - 25 MPa.

[0037] In step 4), when the temperature of the laminate cools down to below 30 °C, open the mold to take out the laminated product.

[0038] Furthermore, when the surface density of the laminated product is 10.0 Kg / m 2 After testing, its V50 value ≥ 900 m / s, preferably ≥ 950 m / s, more preferably ≥ 1000 m / s, still more preferably ≥ 1100 m / s, and most preferably ≥ 1200 m / s.

[0039] The ballistic protection limit index V50 (Ballistic limit protection criteria V50, hereinafter referred to as V50) refers to the average impact velocity of the projectile (including bullets, explosive fragments, etc.) when the penetration probability of the tested armor material is 50%.

[0040] Furthermore, the said laminated product can be applied to fields such as lightweight bulletproof vests, bulletproof blankets, building protection layers, bomb isolation facilities, bulletproof and stab-proof double bulletproof vests, lightweight stab-proof vests, bulletproof chest inserts, bulletproof shields, bulletproof armor plates, bulletproof helmets, and structural / semi-structural components with high requirements for lightweight and high rigidity.

[0041] Beneficial effects:

[0042] During the processing of ultra-high molecular weight polyethylene films, a certain number of defects are inevitably generated, which are intuitively manifested as a decrease in density. The lower the density, the more defects in the UHMWPE film, and the greater the possibility of material failure during subsequent use.

[0043] The present invention reveals the correlation between the density and elastic modulus of UHMWPE films through a large amount of experimental data, and creatively obtains the relational expression between the elastic modulus and density of the film: M > 141D + 7, where M is the value of the elastic modulus in GPa, and D is the density value in g·cm -3 , which intuitively reflects that it is only possible to prepare a film with a higher elastic modulus when the density does not decrease significantly, and has important guiding significance for the adjustment and optimization of the preparation process parameters of UHMWPE films.

[0044] Through a large number of experiments, the inventor surprisingly found that the amount of defects in the ultra-high molecular weight film that satisfies this relational expression is reduced, and the degree of orientation and crystallinity are further improved, that is, the synchronous improvement of properties such as elastic modulus (or mechanical properties), degree of orientation (regularity of molecular chain arrangement), and crystallinity (perfection of internal structure) can be achieved, so that the performance retention rate in the laminate is higher and the V50 value is higher after undergoing an extreme pressing process.

[0045] In addition, due to the significant increase in the width or width-to-thickness ratio of the UHMWPE film, laminate products can be prepared directly by gluing and multi-layer cross-composite without splicing. There are no splicing gaps in each layer of the laminate products, minimizing the possibility of material failure caused by stress concentration caused by splicing gaps.

[0046] Therefore, the laminate products prepared from the UHMWPE films disclosed in the present invention have more excellent impact resistance. Under the same areal density, a large increase in the protection level can be achieved, and under the same protection level, the areal density of the laminate can be greatly reduced, thus achieving the goal of further lightening the weight of protective equipment and having broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a corresponding relationship diagram composed of the elastic modulus and density of the ultra-high molecular weight polyethylene film. DETAILED DESCRIPTION OF THE INVENTION

[0048] In the present invention, the density D is measured by the buoyancy method, that is, the weights of the UHMWPE film in air and water (W0 and W1, in g) are weighed respectively, and the density (in g·cm -3 ) is calculated by the following formula:

[0049]

[0050] In the present invention, the elastic modulus is measured by the method specified in ASTM D882-18 Standard Test Method for Tensile Properties of Thin Plastic Sheeting. The gauge length is 150 mm, the tensile speed is 25 mm / min, the width of the specimen is 8 mm, and the initial force is 0-2 N. The elastic modulus is calculated by dividing the tensile stress at any point on the tangent line of the initial straight-line part of the force-elongation curve by the corresponding strain, and can be directly given by the test software. In the present invention, it is expressed in the unit of GPa.

[0051] In the present invention, the crystallinity X% is measured by DSC method, that is, the melting enthalpy H of the UHMWPE film is measured, and the melting enthalpy H0 of 100% crystalline polyethylene is 293 J.g -1 is used as the standard, and the crystallinity is calculated by the following formula:

[0052]

[0053] In the present invention, the degree of orientation is measured by the sound velocity method. The method measures the average degree of orientation of the crystalline region and the amorphous region, reflects the degree of orientation of the entire molecular chain, and can more intuitively represent the degree of orientation of the molecular chain in the material. The degree of orientation F% can be calculated by the propagation velocity C of the sound velocity in the processing direction of the UHMWPE film and the propagation velocity C in completely non-oriented polyethylene u through the following formula:

[0054]

[0055] where C u is generally taken as 1.655 km / s.

[0056] Definition of the ballistic protection limit index V50 in the present invention: the average impact velocity of the simulated fragment or specific projectile when the penetration probability is 50%. When the ballistic material is subjected to the penetration test, the average value of a certain number of the highest effective penetration velocities and the same number of the lowest effective complete penetration velocities is taken.

[0057] The calculation formula of V50 is as follows:

[0058] That is:

[0059] where: n is the number of effective projectile shots measured by the instrument; V i is the velocity of the i-th effective test projectile at the instrument velocity measurement point, m / s.

[0060] Then, the V50 value is calculated as follows:

[0061]

[0062] Where: V50 is the terminal velocity of the warhead or fragment hitting the target, in m / s; ΔV is the attenuated velocity from the velocity measurement point to the target point, in m / s.

[0063] UHMWPE powder with a viscosity-average molecular weight of 5.2 million, a crystallinity of 76%, and a melting point of 141 °C, which is self-made by the company, is formed into a UHMWPE base film with a width of 1200 mm and a thickness of 720 μm in a hot pressing device at 135 °C. After testing, the density of the base film can reach 0.96 g / cm 3 , approaching its theoretical density.

[0064] Example 1

[0065] The above UHMWPE base film is successively stretched 4 times, 3 times, 2 times, and 1.3 times in a hot stretching machine at 140 °C, 146 °C, 152 °C, and 157 °C respectively, to obtain a UHMWPE film with a total stretching multiple of 31.2 times in the processing direction. After testing, the width of the prepared UHMWPE film is 903 mm, the thickness is 35 μm, the width-thickness ratio is 25800, the elastic modulus is 127 GPa, and the density is 0.83 g.cm -3 , the crystallinity is 78.0%, and the orientation degree is 91.0%.

[0066] Compared with Example 1, in Examples 2 - 30, the stretching temperature, stretching multiple, and total stretching multiple of the UHMWPE base film in the hot stretching machine are adjusted to prepare ultra-high molecular weight polyethylene films with different properties. The specific experimental data are shown in Table 1.

[0067] Comparative Example 1

[0068] Using the same base film as in the example, it is stretched 4 times, 2.5 times, 1.5 times, and 1.2 times in a hot stretching machine at 140 °C, 146 °C, 152 °C, and 157 °C respectively, to obtain a UHMWPE film with a total stretching multiple of 18 times in the processing direction. After testing, the width of the prepared UHMWPE film is 960 mm, the thickness is 47 μm, the width-thickness ratio is 20426, the elastic modulus is 83 GPa, and the density is 0.93 g.cm -3 , the crystallinity is 71.0%, and the orientation degree is 82.3%. This film has a relatively large width-thickness ratio and a relatively high density, but due to the relatively small drawing ratio, its elastic modulus is relatively low and does not satisfy the relationship between the elastic modulus and density in the present invention.

[0069] Comparative Example 2

[0070] Using the same base film as in the examples, it was stretched 4 times, 3 times, 2.3 times, and 1.5 times respectively in a hot stretching machine at 140 °C, 146 °C, 152 °C, and 157 °C to obtain a UHMWPE film with a total draw ratio of 41.4 times in the processing direction. After testing, the width of the prepared UHMWPE film was 840 mm, the thickness was 27 μm, the width-to-thickness ratio was 31111, the elastic modulus was 107 GPa, and the density was 0.80 g·cm -3 , the crystallinity was 82.1%, and the orientation degree was 91.3%. This film has a large width-to-thickness ratio. However, due to the poor matching between the stretching temperature and the stretching ratio, the stretching temperature was relatively low, and more defects were formed in the film, which was intuitively manifested as a significant decrease in density. Even at a relatively high draw ratio, a film with a significantly increased elastic modulus could not be obtained. This type of film does not satisfy the relationship between the elastic modulus and the density in the present invention.

[0071] Comparative Example 3

[0072] Using the same base film as in the examples, it was stretched 4 times, 3 times, 2 times, and 1.3 times respectively in a hot stretching machine at 140 °C, 146 °C, 153 °C, and 157 °C to obtain a UHMWPE film with a total draw ratio of 31.2 times in the processing direction. After testing, the width of the prepared UHMWPE film was 905 mm, the thickness was 34 μm, the width-to-thickness ratio was 26618, the elastic modulus was 127 GPa, and the density was 0.86 g·cm -3 , the crystallinity was 78.3%, and the orientation degree was 90.9%. Both the elastic modulus and the density of this film are relatively high, but it does not satisfy the relationship described in the present invention.

[0073]

[0074]

[0075] (3) Secondary hot pressing

[0076] When the mold temperature stabilizes at 130 °C, increase the pressure to 22.5 MPa, observe and record the actual temperature of the material being pressed. After ensuring that the core temperature of the material plate remains constant at 130 °C, continue to keep the temperature and pressure constant for 30 minutes.

[0077] (4) Cooling and mold opening

[0078] Maintain a constant pressure of 22.5 MPa, cool the mold, and control the process cooling rate of the mold (the cooling rate of the mold surface is not greater than 6 °C / min, and the cooling rate of the laminate is not greater than 4 °C / min). After the temperature of the laminate drops below 30 °C, open the mold and take out the laminate.

[0079] Measure the V50 of each of the 33 laminates prepared above.

[0080] Table 2: V50 test results of 33 laminates prepared in the present invention.

[0081]

[0082]

[0083] In the examples and comparative examples of the present invention, a series of UHMWPE film samples with different combinations of properties such as width, thickness, width-to-thickness ratio, crystallinity, orientation degree, density, and elastic modulus were prepared by optimizing and adjusting the stretching temperature and stretching ratio. Laminates were made from the above-mentioned films, and V50 tests of their impact resistance were carried out. The laminates prepared from the samples of Examples 1-30 all had high V50 values, that is, excellent impact resistance was obtained. The inventor fitted the experimental data including Examples 1-30 and obtained Figure 1 a relationship diagram (the abscissa is density and the ordinate is elastic modulus), M is the elastic modulus with the unit of GPa, D is the density with the unit of g.cm -3 , and the black diagonal line is the straight line formed by M = 141D + 7. The data points corresponding to the elastic modulus and density in the examples are all above the black diagonal line, that is, the relationship formula M > 141D + 7.

[0084] It can be seen that there is a certain correlation between the elastic modulus and density of the UHMWPE film of the present invention. Under the same stretching ratio, the higher the density, the higher the elastic modulus of the film. When the density is reduced to a certain extent (such as below 0.8 g.cm -3 ), it is difficult to further increase the elastic modulus of the film only by increasing the stretching ratio. Only by continuing to increase the stretching ratio at a further adapted drawing temperature while ensuring that the film density does not decrease significantly, can the elastic modulus of the film be further improved. The above relationship formula intuitively shows the limiting effect of the density of ultra-high molecular weight polyethylene film on the elastic modulus, which has important guiding significance for optimizing the process parameters. If it is necessary to further increase the elastic modulus of the film, the film density should be increased as much as possible, or only by optimizing and adjusting the stretching process parameters while ensuring that the density does not decrease can the means of further increasing the elastic modulus of the film be effective. If the density decreases significantly during the stretching process, even if the stretching ratio is increased significantly, the elastic modulus will not show a significant increase (such as Comparative Example 2).

[0085] In addition, the examples and comparative examples in Table 1 also show that only when the draw ratio exceeds a specific value, can the indicators such as the crystallinity, orientation degree, and mechanical properties of the film be significantly improved, and thus the impact resistance of the laminate made from the film can be significantly enhanced. When the draw ratio is small (such as in Comparative Example 1), since the above indicators are relatively low, even if the film density is high, the impact resistance of the laminate made is relatively poor. Thus, the limiting conditions for the crystallinity, orientation degree, and elastic modulus of the film in the present invention are given.

[0086] Finally, the matching of the draw ratio and draw temperature in each stage is crucial for obtaining a UHMWPE film with the performance required by the formula. Under the condition that the draw ratio is moderate but the temperature matching in a certain draw stage is inappropriate, even if a UHMWPE film with relatively high density and elastic modulus can be obtained (such as in Comparative Example 3), its elastic modulus and density are still not high, and the impact resistance of the laminate made from this film is still inferior to that of the film with better matching of the draw ratio and draw temperature in each stage and satisfying the relational expression of the present invention.

Claims

1. A ultra-high molecular weight polyethylene film, wherein the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is greater than 500,000, and wherein, The film density D is greater than 0.80 g / cm -3 , the elastic modulus M is greater than 120 GPa, and it is characterized in that: the elastic modulus and density of the ultra-high molecular weight polyethylene film satisfy the following relational expression: M > 141D + 7.

2. The ultra-high molecular weight polyethylene film according to claim 1, wherein: The total draw ratio of the film in one direction is at least 25 times.

3. The ultra-high molecular weight polyethylene film according to claim 1, wherein: The thickness T of the film is ≥ 10 μm.

4. The ultra-high molecular weight polyethylene film according to claim 1, wherein: The width W of the film is ≥ 300 mm.

5. The ultra-high molecular weight polyethylene film according to claim 1, characterized in that: The aspect ratio of the film is greater than or equal to 10,000.

6. The ultra-high molecular weight polyethylene film according to claim 1, wherein: The crystallinity of the film is ≥ 75%.

7. The ultra-high molecular weight polyethylene film according to claim 1, characterized in that: The degree of orientation of the film is ≥ 90%.

8. An article of a laminated ultra-high molecular weight polyethylene film, which comprises a plurality of films as described in any one of claims 1-7, each single layer being composed of one film or made by splicing a plurality of films, characterized in that: The maximum orientation direction of each single layer is different from that of the next single layer.

9. The ultra-high molecular weight polyethylene film laminate article according to claim 8, wherein The laminate product is prepared by the following steps: 1) Layering single layers obtained by cutting and / or splicing multiple ultra-high molecular weight polyethylene films to form a material to be pressed, place it in a laminating mold, and close the mold; 2) Perform primary hot pressing on the multiple single layers prepared in step 1) to form a preform; 3) Perform secondary hot pressing on the preform prepared in step 2); 4) Cool the mold and open the mold to take out the laminate product.

10. The ultra-high molecular weight polyethylene film laminate product according to any one of claims 8-9, characterized in that: The areal density of the laminate product is 10.0 Kg / m 2 When it is, its V50 value ≥ 900 m / s.

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