Polyethylene resin for electronic protection film, and preparation method and application thereof

Abstract

This invention provides a polyethylene resin for electronic protective films, its preparation method, and its application. The weight-average molecular weight of this polyethylene resin is denoted as x1, the long-chain branch content as x2, and the zero-shear viscosity as y. x1, x2, and y satisfy the following relationship: y ≥ 0.12709x1 + 2.57189 × 10⁻⁶. 7 x2-24802.3; wherein, the weight-average molecular weight x1 of the polyethylene resin ranges from 55000 to 75000 g / mol, the long-branch content x2 of the polyethylene resin is ≤0.95‰, and the molecular weight distribution index of the polyethylene resin ranges from 3.0 to 3.8. The electronic protective film prepared from the polyethylene resin of this invention has a relatively low number of crystal points, ≤0.5 per m. 2 It can meet industrial requirements.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plastic processing application, and relates to a polyethylene resin for electronic protective film, a preparation method of the polyethylene resin and application of the polyethylene resin. BACKGROUND

[0002] As one of the five synthetic resins, polyethylene has a wide market application value, is one of indispensable articles in people's daily life, and is the most product among synthetic resins in China. Polyethylene is mainly divided into three categories, namely, low density high pressure polyethylene (Low density polyethylene, LDPE for short), linear low pressure low density polyethylene (Linear low density polyethylene, LLDPE for short) and high density low pressure polyethylene (High density polyethylene, HDPE for short). Compared with other polyethylenes, LDPE has good elongation, transparency, processability, stable chemical properties, acid resistance and alkali resistance. Due to its excellent performance, it is widely used in medical, foaming, profile, film and other fields. With the rapid development of the information industry and the large application of high-end optical devices, electronic protective film has become one of the key materials in the high-end electronic and optical fields. During transportation, storage, processing or assembly, it is often necessary to protect the surface of materials and parts from dust pollution or avoid scratches caused by mechanical scratches. One of the commonly used methods is to paste a protective film on the surface of the protected object. After transportation, storage, processing or assembly are completed, the protective film is removed to achieve the purpose of protecting the surface of the material. There is also surface protection of finished products, such as protection of optical lenses of high-end video cameras, surface protection of flat panel computers and light guide plates, etc. If the film crystal point is high, the surface of the protected object will be scratched, causing unnecessary loss.

[0003] The main sources of film crystal points are factors of raw materials themselves, such as polyethylene macromolecules with large molecular weight, cross-linking and long chain branches formed in the polymerization and granulation processes, which may produce crystal points. In addition, crystal points may also be brought in the post-processing process.

[0004] The existing technology has the following methods for controlling crystal points:

[0005] (1) Control of raw materials:

[0006] There are documents (Formation and Countermeasures of "fish eye" in LDPE film, Synthetic Resin and Plastic, 2010, 27 (4): 56 ~ 58), for the problem of "fish eye" too many in low density polyethylene (LDPE) high transparent resin 2436H film, from the production of reaction system, additive adding system to explore the formation of "fish eye". By adjusting the reaction process technology, grade switching sequence, screening of additives, etc. The number of "fish eye" of the first 3 batches of products produced each time is less than 6 / 1200cm 2 , document (Blown film resin fish eye reason analysis and prevention, Heilongjiang Petrochemical, 1996:12) according to the production process of high pressure low density polyethylene, discusses the causes of fish eye in the production of blown film resin, and puts forward the assumption of reducing the number of fish eye in blown film resin according to the current production situation. In the process of producing blown film resin, under the conditions of ensuring high reaction pressure, relatively low reaction temperature and adding antioxidant and other additives, the formation of fish eye in the resin can be effectively inhibited, but the number of crystal point is too much, which cannot meet the requirements of electronic protective film.

[0007] In the patent CN105585765A "a kind of low density polyethylene resin for manufacturing high transparent film and its preparation method", it is disclosed, but it is limited to the increase of transparent performance, butene and propyl aldehyde addition amount accounts for (0-1%) of total reactant mass percentage, butene-1 and propyl aldehyde ratio, wherein butene-1 addition percentage is (0-100%), due to the increase of butene-1 addition amount, the single consumption of initiator will increase compared with using propyl aldehyde alone, at the same time, it will also cause the increase of crystal point number.

[0008] CN105585766A discloses a kind of low density polyethylene resin for pharmaceutical film and its preparation method, the number average molecular weight of the resin is 1-20,000, the molecular weight distribution index is 4-6, the haze range is 4%-9%, the n-hexane extract is 0.5-2g / 100g, the melt flow rate under the pressure of 2.16kg weight at 190℃ is 1.0-5.0g / 10min. The product is prepared by using ethylene as raw material, air and organic peroxide as mixed initiator for polymerization reaction, by adjusting the ratio of 1-butene and propyl aldehyde, first obtaining polyethylene, then mixing the obtained polyethylene with antioxidant and opening agent to obtain a master batch by dry granulation, and then extruding and granulating to obtain a low density polyethylene resin specially used for manufacturing high transparent film. Because air and organic peroxide are used as mixed initiator for polymerization reaction, therefore, external impurities will be brought in.

[0009] The paper "Quality Optimization of Low-Density Polyethylene Resin 2420H for Low Crystalline Point Films" published in Petrochemical Technology and Application, 2020, 38(4) analyzes the causes and influencing factors of crystal point formation in order to solve the problem of excessive crystal points in low-density polyethylene resin 2420H for low crystalline point films, and optimizes the production process. In the production process of polyethylene granulation, the extruder barrel temperature of 185-200℃ is too high. Because of the high extruder temperature, the residual initiator will react further during the extrusion granulation process, thereby increasing the probability of macromolecular gelation and increasing the number of crystal points.

[0010] Methods to control the crystal points of raw materials by improving polymerization processes and additives aim to control the molecular weight and other properties of raw materials. However, from the perspective of market application, the effect is not ideal. At the same time, some control methods add antioxidants, opening agents and other additives. Due to the large number of additive manufacturers and the uneven quality, additives containing impurities will increase the number of crystal points in the film during use.

[0011] (2) Post-processing control:

[0012] US2018 / 9993954 provides a method for preparing a surface protective film, wherein the surface protective film is free from rolling defects such as blockage or wrinkling when rolled into a roll, and after the film is bonded to the substrate, it is rolled into a roll and stored for a long time without transferring unevenness or fisheyes.

[0013] CN 109383044 A describes a method for producing dry film protective film using a casting process. The method involves selecting raw materials with suitable melt flow indexes, such as polyethylene (PE) and polypropylene (PP). After mixing in an automatic mixing system via a conveyor fan, the raw materials undergo negative pressure backflushing and electrostatic dust removal. The dust-removed raw material particles are then melted in three extruders. The melt must be filtered at the connection between the extruder and the die to prevent unmelted material and crystal points from entering the die. This invention offers advantages such as low cost, fewer crystal points, excellent appearance, and ease of control.

[0014] CN 114231203 A A high-unwinding, non-precipitation, high-haze self-adhesive polyethylene protective film and its preparation method, the present application relates to the technical field of optical protective film, provides a kind of high-unwinding, non-precipitation, high-haze self-adhesive polyethylene protective film and its preparation method.The present application forms regular and dense convex point arrangement on the surface of film material by selecting and matching raw materials, so that the adhesive layer and the back layer of the film material are not combined with micro-vacuum negative pressure during unwinding and peeling, which achieves the purpose of easy unwinding and anti-adhesion.In addition, the protective film provided by the present application does not add silicone master batch, and no precipitation occurs during use.The inner layer of the protective film is selected from high-haze high-pressure low-density polyethylene, so that the protective film has high haze and good matte effect.The present application also provides a preparation method for the high-unwinding, non-precipitation, high-haze self-adhesive polyethylene protective film described above.The cooling film bubble temperature is controlled at 20-25 DEG C, the cooling speed of the film bubble is reduced by increasing the air temperature, so that the protective film reaches the required haze.

[0015] CN108437496A Annealing and shaping device for electronic protective film prepared by casting method, the present application discloses an annealing and shaping device for electronic protective film prepared by casting method, comprising: a rack and at least two groups of annealing roller groups arranged on the rack, each annealing roller group is provided with at least two groups of annealing rollers, the annealing rollers of the annealing roller group are distributed in S shape, so that the film material can be wound on the annealing rollers in S shape, the present application can increase the contact time of the film material with the annealing rollers, improve the annealing effect, and the surface of the annealing roller is provided with a non-stick nano coating, which can prevent the accumulation of precipitates, pollution of the film and damage to the adhesive layer, and realize high-temperature annealing and shaping, and meet the quality requirements of electronic protective film in high transparency, viscosity stability and other aspects.

[0016] CN110054849A Environment-friendly electronic protective film and production process thereof, the present application discloses an environment-friendly electronic protective film and production process thereof, and specific components are prepared according to the following weight fractions: PVC resin powder 70-80 parts, transparent calcium powder 3-5 parts, ESO 1-3 parts, polyester plasticizer 20-30 parts, calcium-zinc stabilizer 2-3 parts, colorant 0.1-1 part.The present application optimizes the composition ratio and process control of raw materials, greatly improves the toughness, non-migration and oil resistance of the film under the premise of not increasing the production cost, and has strong market competitiveness.

[0017] CN105567107 A kind of self-adhesive vacuum plating electronic protection film, the application discloses a kind of self-adhesive vacuum plating electronic protection film, including the following components: thermoplastic polyester elastomer;Polyolefin elastomer;PE wax;High-density polyethylene;Polyvinyl alcohol;Nano silicon carbide;Tackifying resin;Antioxidant;Functional monomer and antistatic agent.The application provides a kind of self-adhesive vacuum plating electronic protection film, film surface is not wrinkled, not deformed, adhesive force is stable, good adhesion, peeling performance is good, no residual glue phenomenon, and barrier and mechanical properties are excellent, lower dielectric constant, it is a kind of excellent vacuum plating protection film material, non-toxic, environmentally friendly, safe and practical.

[0018] CN109318556A An electronic protection film and a preparation method thereof, the application relates to an electronic protection film, which comprises three layers of surface layer I, core layer and surface layer II.The surface layer I comprises the following raw materials in parts by weight: matting agent 95-105 parts;The core layer comprises the following raw materials in parts by weight: polypropylene 99.3-99.5 parts, antistatic agent 0.5-0.7 parts;The surface layer II comprises the following raw materials in parts by weight: matting agent 95-105 parts.The electronic protection film of the application has high haze and low gloss, the matting layer has smooth and delicate feel, and the white matte effect is more beautiful.The electronic protection film is used for the surface protection of electronic products, and can prevent dust and scratches during production, thereby increasing the market competitiveness of products, meeting the needs of customers and filling the gap in the market.

[0019] In summary, the post-processing technology mainly focuses on production, gluing and formula, and the crystal point of the film can be appropriately reduced by improving the post-processing technology, but the crystal point caused by the raw material itself cannot be fundamentally eliminated, therefore, it is particularly important to control the molecular chain structure and cleanliness of the raw material to reduce the crystal point.

[0020] So far, in the methods for reducing the crystal point of polyethylene disclosed in scientific and patent literatures, the following defects usually exist:(1) the method for controlling the crystal point of the raw material by improving the polymerization process and additives has some effect, but the effect is not ideal from the market application, and the additives containing impurities will increase the number of crystal points of the film in the use process due to the uneven quality of the additives from different manufacturers and the addition of antioxidants and opening agents.(2) the crystal point of the film can be appropriately reduced by the post-processing technology, but the crystal point caused by the raw material itself cannot be fundamentally eliminated, therefore, it is particularly important to control the molecular chain structure and cleanliness of the raw material to reduce the crystal point, so as to meet the increasing market demand for electronic protection film raw materials. SUMMARY

[0021] The polyethylene resin for electronic protection film, the preparation method and application thereof can overcome the defects of the electronic protection film prepared by using the polyethylene resin as raw material in the prior art, such as more crystal points and difficulty in meeting the application requirements.

[0022] In order to achieve the above-mentioned purpose, the polyethylene resin for electronic protection film is provided, the weight average molecular weight of the polyethylene resin is denoted as x1, the long chain branch content is denoted as x2, and the zero shear viscosity is denoted as y, x1, x2 and y satisfy the following relationship: y >= 0.12709x1+2.57189x2-24802.3 7 x2-24802.3;

[0023] The weight average molecular weight x1 of the polyethylene resin ranges from 55000 to 75000 g / mol, the long chain branch content x2 of the polyethylene resin is <= 0.95 ‰, and the molecular weight distribution index of the polyethylene resin ranges from 3.0 to 3.8.

[0024] The polyethylene resin for electronic protection film, wherein the powder content of the polyethylene resin is <= 30 ppm.

[0025] In order to achieve the above-mentioned purpose, the polyethylene resin for electronic protection film is provided, the preparation method thereof is also provided, which comprises the following steps:

[0026] Step 1, ethylene is pressurized to 260 Mpa-270 Mpa and the temperature is 165℃-168℃, then the ethylene is introduced into a reactor to perform a polymerization reaction under the initiation of an organic peroxide, so as to obtain polyethylene;

[0027] Step 2, the polyethylene obtained in step 1 is extruded and granulated, the temperature of the extruder barrel is 140-170℃, so as to obtain the polyethylene resin.

[0028] The preparation method of the polyethylene resin for electronic protection film, wherein the organic peroxide is diluted with isododecane before being added into the reactor, so as to obtain diluted organic peroxide, the mass concentration of the organic peroxide in the diluted organic peroxide is 5%-20%; the organic peroxide is 2-ethylhexyl peroxydicarbonate, di-tert-butyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl hexanoate, tert-butyl ethylhexanoate, tert-butyl peroxypivalate and tert-amyl ethylhexanoate.

[0029] The preparation method of the polyethylene resin for electronic protection film, wherein the organic peroxide is diluted in an inert gas environment.

[0030] The method for preparing polyethylene resin for electronic protective film according to the present invention, wherein, based on the total addition amount of ethylene, organic peroxide and molecular weight regulator being 100%, the addition amount of organic peroxide is 0.01wt%-0.3wt%.

[0031] The method for preparing polyethylene resin for electronic protective film according to the present invention includes a polymerization reaction pressure of 265-275 MPa and a polymerization reaction temperature of 280-289°C.

[0032] The method for preparing polyethylene resin for electronic protective film according to the present invention includes adding a molecular weight regulator during the polymerization reaction. The molecular weight regulator is at least one selected from propane, isobutane, acetone, propylene, isopropanol, butene-1, and propionaldehyde. The amount of the molecular weight regulator added is 0.05wt%-0.5wt%, based on the total amount of ethylene, organic peroxide, and molecular weight regulator added being 100%.

[0033] The method for preparing polyethylene resin for electronic protective film according to the present invention, wherein the molecular weight regulator is a mixture of propionaldehyde and butene-1, and the mass ratio of propionaldehyde to butene-1 is 7:3-3:7.

[0034] To achieve the above objectives, the present invention further provides an electronic protection film prepared from the aforementioned polyethylene resin, wherein the number of crystal points is ≤0.5 / m. 2 Crystal point size ≤ 500 micrometers.

[0035] The beneficial effects of this invention are:

[0036] The weight-average molecular weight (x1) of the polyethylene resin used in the electronic protective film of this invention ranges from 55,000 to 75,000 g / mol, preferably from 60,000 to 70,000 g / mol. The long-chain branch content (x2) of the polyethylene resin is ≤0.95‰, and the molecular weight distribution index (MDI) of the polyethylene resin ranges from 3.0 to 3.8, satisfying the following relationship: y≥0.12709x1+2.57189×10 7 x2-24802.3; This results in a lower number of crystal points in the electronic protective film prepared from the polyethylene resin of the present invention, ≤0.5 points / m. 2 Furthermore, the crystal point size is ≤500 micrometers, which meets industrial requirements.

[0037] The method for preparing polyethylene resin in this invention is simple. By pre-treating the ethylene raw material and controlling the pressure and temperature of the extruder barrel, the possibility of long-chain branches and macromolecular gel formation in the polyethylene resin is greatly reduced, which helps to reduce the crystal points of subsequent electronic protective film products made from polyethylene. Attached Figure Description

[0038] Figure 1 Evaluation results of the crystal points of the trial production sample 5 of Example 5 of the present application;

[0039] Figure 2 Evaluation results of the crystal points of the comparative sample 1 of Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0040] The following detailed description of the embodiments of the present application is made on the premise of the technical solutions of the present application, and detailed implementation manners and processes are given, but the protection scope of the present application is not limited to the following embodiments. The experimental methods not specified in the following embodiments are usually performed according to the conventional conditions.

[0041] The present application provides a polyethylene resin for electronic protective film, the weight average molecular weight of the polyethylene resin is denoted as x1, the long chain branch content is denoted as x2, and the zero shear viscosity is denoted as y, x1, x2 and y satisfy the following relationship: y≥0.12709x1+2.57189x2-24802.3 7 .

[0042] The weight average molecular weight x1 of the polyethylene resin ranges from 55000 to 75000 g / mol, the long chain branch content x2 of the polyethylene resin is ≤0.95 ‰, and the molecular weight distribution index of the polyethylene resin ranges from 3.0 to 3.8. In the long chain branch content, the long chain branch refers to a branch with more than 10 carbons in the polyethylene, and the long chain branch content is the number of long chain branches contained in 1000 carbon atoms of the polyethylene, that is, the number of branches with more than 10 carbons contained in 1000 carbon atoms of the polyethylene.

[0043] The present application limits the range of the weight average molecular weight and the long chain branch content of the polyethylene resin, and makes the weight average molecular weight, the long chain branch content and the zero shear viscosity of the polyethylene resin satisfy a specific quantitative relationship, so as to control the molecular chain structure of the polyethylene resin, and further make the electronic protective film prepared from the polyethylene resin have fewer crystal points, ≤0.5 / m 2 , which meets the subsequent industrial requirements.

[0044] In an embodiment, the zero shear viscosity of the polyethylene resin of the present application is measured by a rheological method, the weight average molecular weight of the polyethylene resin is measured by a GPC method, and the long chain branch content of the polyethylene resin is measured by a rheological method. The molecular weight distribution index of the polyethylene resin of the present application ranges from 3.0 to 3.8, the molecular weight distribution is narrow, and the factors causing the generation of crystal points when the polyethylene resin is used to prepare electronic protective film are reduced.

[0045] In an embodiment, the polyethylene resin of the present application has a powder content of ≤ 30 ppm, wherein the powder content of the polyethylene resin refers to the content of the powder contained in the polyethylene after pelletization. The present application provides a method for determining the powder content of the polyethylene resin, which is as follows:

[0046] About 500 g of the polyethylene resin is weighed and marked as (W1), and then sieved through a 100-mesh sieve for 5 min, and then weighed again and marked as (W2), with an accuracy of 0.00001 g. The powder content is calculated using the following formula:

[0047] Powder content = (W1-W2) / W1 x 100%

[0048] The polyethylene resin of the present application can meet the powder content requirement when it is prepared into a resin, or the powder in the polyethylene resin can be removed by a dust removal device during the pelletization stage, so that the polyethylene resin meets the powder content requirement. The present application is not particularly limited.

[0049] In an embodiment, the present application provides a method for preparing the polyethylene resin for the electronic protective film, which comprises the following steps:

[0050] Step 1: ethylene is pressurized to 260-270 MPa and heated to 165-168℃, and then introduced into a reactor, and a polymerization reaction is carried out under the initiation of an organic peroxide to obtain a polyethylene;

[0051] Step 2: the polyethylene obtained in step 1 is extruded and pelletized, and the temperature of the extruder barrel is 140-170℃, to obtain a polyethylene resin.

[0052] By controlling the temperature of the extruder barrel, the present application can avoid further initiation of the polymerization reaction by the initiator during the extrusion and pelletization stage, thereby greatly reducing the possibility of the generation of long-chain branches and macromolecular gels, which is helpful to reduce the crystal points of the electronic protective film.

[0053] In an embodiment, the polyethylene resin of the present application is prepared by a tubular high-pressure polymerization process. Fresh ethylene and unreacted ethylene in the reactor are pressurized to 260-270 MPa and heated to 165-168℃ by a two-stage compressor, and then delivered to a reactor, and a polymerization reaction is carried out under the initiation of an organic peroxide to obtain a polyethylene.

[0054] The organic peroxide is at least one of 2-ethylhexylperoxydicarbonate (EHP), di-tert-butylperoxide (DTBP), tert-butyl peroxybenzoate (TBPB), tert-butyl peroxy-2-ethylhexanoate (TBPO), tert-butyl peroxyhexanoate (TBPIN), tert-butyl peroxyethylhexanoate (TBPEH), tert-amyl peroxyethylhexanoate (TAPEH), tert-butyl peroxyperoxy pivalate (TBPPI). In one embodiment, the organic peroxide of the present application is diluted with isododecane before being fed into the reactor to obtain a diluted organic peroxide, and the mass concentration of the organic peroxide in the diluted organic peroxide is 5% to 20%. In one embodiment, the mass concentration of the organic peroxide in the diluted organic peroxide is different in the four reaction zones of the reactor, for example, 16%, 9%, 7%, and 7% respectively. By diluting the organic peroxide before feeding into the reaction system, the present application can reduce the residual organic peroxide in the obtained resin, reduce the possibility of crosslinking between molecular weights in the later granulation process, reduce the content of long chain branches in the polyethylene resin, narrow the molecular weight distribution width of the polyethylene resin, and further reduce the number of crystal points of the electronic protective film prepared from the resin.

[0055] The organic peroxide of the present application is protected by inert gas, for example, nitrogen, during the transportation, dilution and feeding into the reactor.

[0056] In one embodiment, the amount of the organic peroxide of the present application fed into the reactor is 0.01% to 0.3% (calculated by mass percentage), and is continuously fed by three pump heads to meet the stability requirements of the resin quality, wherein the amount of the organic peroxide is calculated based on the total amount of ethylene, organic peroxide and molecular weight regulator as 100%.

[0057] In one embodiment, a molecular weight regulator is added during the polymerization process of the present application, and the molecular weight regulator is at least one of propane, isobutane, acetone, propylene, isopropyl alcohol, butene-1, and propyl aldehyde, and the amount of the molecular weight regulator added is 0.05wt% to 0.5wt% (calculated based on the total amount of ethylene, organic peroxide and molecular weight regulator as 100%). In another embodiment, the molecular weight regulator of the present application is preferably a combination of propyl aldehyde and butene-1, and the amount of the combination added is 0.05wt% to 0.5wt% (calculated based on the total amount of ethylene, organic peroxide and molecular weight regulator as 100%), and the mass ratio of propyl aldehyde to butene-1 is 7:3 to 3:7, preferably 5:5. The combination of the above can control the long mass content and molecular weight distribution of the polyethylene resin of the present application within the required range by controlling the temperature of the extruder barrel during granulation.

[0058] The pressure of the polymerization reaction is 265 to 275 MPa, preferably 266 to 272 MPa, and the temperature of the polymerization reaction is 280 to 289°C, preferably 284 to 288°C.

[0059] Thus, the present application controls the molecular chain structure of the product by selecting suitable pressure, peak temperature, initiator and molecular weight regulator, by controlling the long chain branch content, molecular weight and distribution, zero shear viscosity in the molecular chain structure, and the specific relationship thereof, and by effectively combining the control of the powder content, the crystal point of the raw material is effectively controlled. The crystal point of the electronic protective film prepared from the polyethylene resin of the present application is ≤0.5 / m 2 wherein the crystal point size is ≤500 microns, meeting the industrial requirements.

[0060] The technical solutions of the present application will be further described in detail below through specific examples.

[0061] Analysis method:

[0062] Relative molecular mass and distribution method: determined by using Alliance GPCV2000 of the United States Waters Company, the sample usage is 8 mg, the sample is dissolved in the flowing phase dichlorobenzene solvent, the solution is injected into the chromatographic column for testing, and the testing temperature is 135℃.

[0063] Crystal point: tested by using the SCD-50 type crystal point instrument of the Haap Company. The sample is extruded into a sheet at the extruder head temperature of 170℃, the rotating speed is 10 rpm, the thickness is 20 um, and the width is 5 cm. The crystal point detector detects 33.6m 2 The number of crystal points on the sample sheet.

[0064] Long chain branch content testing method: using the AR-G2 rheometer of the United States TA Company, the testing temperature is 190℃, the testing frequency is 0.06283-628.3 r / s, and the strain is 1%. The loss angle δ corresponding to a certain modulus value (|G*| = 10 kPa) is used to calculate the long chain branch content LCBI according to the formula LCBI = 2.5085-2.8178 x 10 -2 δ is used to calculate the long chain branch content LCBI.

[0065] Zero shear viscosity testing method: using the dynamic rheometer AR-G2 of the United States TA Company, the testing temperature is 190℃, the testing shear rate range is 0.01-10 1 / s, the Arrhenius equation logK = 1gA- E / 2.303TR is used to perform linear regression on logK and 1 / T, and the zero shear viscosity is obtained.

[0066] In the formula: k is the reaction rate constant at temperature T; A is the pre-exponential factor, also known as the Arrhenius constant, with the same unit as k; E is the activation energy, kJ / mol; T is the absolute temperature, K; and R is the gas constant, kJ / mol·K.

[0067] Example 1

[0068] With ethylene as raw material, the addition amount is 99.86g, the ethylene is pressurized to 262Mpa, the temperature is 165℃, and the organic peroxide is used as the initiator for polymerization reaction. The peroxide is added in four points, and the DTBP, TBPIN, TBPEH and TBPPI are compounded, the mass ratio of peroxide is DTBP: TBPIN: TBPEH: TBPPI is 1:2:2:2, the peroxide injection unit is diluted with organic solvent (isododecane) to the appropriate concentration, that is, the mass concentration of organic peroxide in the four zones of the reactor is 16wt%, 9wt%, 7wt% and 7wt% respectively, the mass ratio of peroxide addition in four zones is 16:9:7:7, the total addition amount is 0.02g, the polymerization pressure is 268Mpa, the polymerization temperature is 288.5℃, the amount of propionaldehyde and butene-1 is adjusted to wt% (7:3), the total addition amount is 0.12g, polyethylene is obtained first, then it is extruded and granulated, the temperature of the extrusion granulator is 170℃, and the sample is treated for powder removal, and polyethylene resin trial production sample 1 is obtained, and the performance is shown in Table 1.

[0069] Table 1 performance test results of trial production sample 1

[0070]

[0071]

[0072] The value calculated according to 0.12709x1+2.57189x10 7 x2-24802.3 of trial production sample 1 is 7891, the measured value y of zero shear viscosity is 7920, which meets the specific relationship (y≥0.12709x1+2.57189x10 7 x2-24802.3), and the application in downstream manufacturers can meet the requirements of electronic protection film.

[0073] Example 2

[0074] Ethylene as raw material, the amount of 99.885g, the ethylene pressure to 260Mpa, the temperature is 166℃, with organic peroxide as initiator for polymerization reaction, peroxide using four-point injection method, peroxide with di-tert-butyl peroxide (DTBP), t-butyl hexanoate (TBPIN), ethylhexanoic acid t-butyl ester (TBPEH), t-butyl peroxypivalate (TBPPI) compound, peroxide mass ratio DTBP: TBPIN: TBPEH: TBPPI is 4:3:2:2, peroxide injection unit with organic solvent (isododecane) to dilute the above peroxide to the appropriate concentration, that is, in the reactor four zone said dilution of organic peroxide organic peroxide mass concentration is 14%, 7%, 5%, 5%, the four zone peroxide addition mass ratio is 14:7:5:5, the total amount of 0.015g, polymerization pressure 272Mpa, polymerization temperature 285℃, adjusting propionaldehyde and butene-1 dosage wt% (6:4), the amount of 0.1g, first get polyethylene, then extrusion granulation, the temperature of extrusion granulator is 170℃, get polyethylene resin test production sample 2, and the sample is treated, the performance is shown in table 2.

[0075] Table 2 test production sample 2 performance test results

[0076] project Trial production sample 2 Melt flow rate, g / 10min 1.890 Weight-average molecular weight, g / mol 68400 Molecular weight distribution index 3.3 Long branched chain content, ‰ 0.9499 Zero-shear viscosity, Pa.s 8350 Powder content, ppm 21 Total number of crystal points, pieces / m 2 ]] 0.45

[0077] The calculated value of test production sample 2 according to 0.12709x1+2.57189x10 7 x2-24802.3 is 8321, the measured value of zero shear viscosity y is 8350, which meets the specific relationship (y≥0.12709x1+2.57189x10 7 x2-24802.3), and can meet the requirements of electronic protective film when applied in downstream manufacturers.

[0078] Example 3

[0079] Ethylene as raw material, the amount of 99.832g, ethylene to 265Mpa, temperature is 167℃, with organic peroxide as initiator for polymerization reaction, peroxide using four point injection method, peroxide with di-tert-butyl peroxide (DTBP), t-butyl hexanoate (TBPIN), ethylhexanoic acid tert-butyl ester (TAPEH), tert-butyl peroxide tert-butyl peroxide (TBPPI) compound, peroxide mass ratio of DTBP: TBPIN: TAPEH: TBPPI is 6:3:2:2, peroxide injection unit with organic solvent (isododecane) to dilute the above peroxide to the appropriate concentration, namely in the reactor four zone said dilution of organic peroxide organic peroxide mass concentration is 13%, 7%, 6%, 5%, four zone peroxide addition mass ratio is 13:7:6:5, the total amount of 0.018g, with ethylene as raw material, with organic peroxide as initiator for polymerization reaction, polymerization pressure 269Mpa, polymerization temperature 286℃, adjusting propionaldehyde and butene-1 dosage wt% (5:5), the amount of 0.15g, first get polyethylene, then extrusion granulation, the temperature of extrusion granulator is 150℃, get polyethylene resin test production sample 3, and the sample is treated, the performance is shown in table 3.

[0080] Table 3 test production sample 3 performance test results

[0081] project Trial production sample 3 Melt flow rate, g / 10min 2.100 Weight-average molecular weight, g / mol 67500 Molecular weight distribution index 3.35 Long branched chain content, ‰ 0.94 Zero-shear viscosity, Pa.s 7961 Powder content, ppm 21 Total number of crystal points, pieces / m 2 ]] 0.38

[0082] Test production sample 3 according to 0.12709x1+2.57189x10 7 2-24802.3 is 7952, the measured value of zero shear viscosity y is 7961, which meets the specific relationship (y≥0.12709x1+2.57189x10 7 2-24802.3), in the downstream factory application, can meet the requirements of electronic protection film.

[0083] Example 4

[0084] Ethylene as raw material, the amount of 99.861 g, the ethylene pressure to 267 Mpa, the temperature is 167 ℃, with organic peroxide as initiator for polymerization reaction, peroxide using four point injection method, with di-tert-butyl peroxide (DTBP), tert-butyl hexanoate (TBPIN), tert-butyl peroxide tert-butyl peroxide (TBPPI) compound, the mass ratio of peroxide DTBP: TBPIN: TBPPI is 3:1:1, peroxide injection unit with organic solvent (isododecane) to dilute the above peroxide to the appropriate concentration, that is, the mass concentration of organic peroxide in the four zones of the reactor is 13%, 7%, 7%, 5%, the mass ratio of peroxide added in four zones is 13:7:7:5, the total amount is 0.019 g, with organic peroxide as initiator for polymerization reaction, polymerization pressure 271 Mpa, polymerization temperature 287 ℃, adjusting the amount of propionaldehyde and butene-1 wt% (3:7), the total amount is 0.12 g, first get polyethylene, then perform extrusion granulation, the temperature of extrusion granulator is 160 ℃, get polyethylene resin test production sample 4, and the sample is treated, the performance is shown in table 4.

[0085] Table 4 test production sample 4 performance test results

[0086] project Trial production sample 4 Melt flow rate, g / 10min 2.001 Weight-average molecular weight, g / mol 70000 Molecular weight distribution index 3.43 Long branched chain content, ‰ 0.9389 Zero-shear viscosity, Pa.s 8277 Powder content, ppm 21 Total number of crystal points, pieces / m 2 ]] 0.42

[0087] The calculated value of test production sample 4 according to 0.12709x1+2.57189x10 7 x2-24802.3 is 8241, the measured value of zero shear viscosity y is 8277, which meets the specific relationship (y≥0.12709x1+2.57189x10 7 x2-24802.3), and can meet the requirements of electronic protective film when applied in downstream manufacturers.

[0088] Example 5

[0089] With ethylene as raw material, the amount of addition is 99.777g, the polymerization reaction is carried out by increasing the pressure of ethylene to 270Mpa and the temperature to 168℃, and organic peroxide is used as initiator. The peroxide is added in four points, and di-tert-butyl peroxide (DTBP), tert-butyl ethylhexanoate (TBPEH) and tert-butyl peroxypivalate (TBPPI) are used in combination. The ratio of peroxide is DTBP:TBPEH:TBPPI=10:5:2. The peroxide injection unit is diluted with organic solvent (isododecane) to the appropriate concentration, i.e. the mass concentration of organic peroxide in the four zones of the reactor is 13%, 6%, 6% and 4% respectively. The mass ratio of peroxide added in the four zones is 13:6:6:4, and the total amount of addition is 0.023g. The polymerization reaction is carried out using organic peroxide as initiator, the polymerization pressure is 266Mpa, the polymerization temperature is 289℃, the amount of propionaldehyde and butene-1 is adjusted to wt% (4:5), the amount of addition is 0.20g. First, polyethylene is obtained, then it is extruded and granulated, the temperature of the extrusion granulator is 160℃, polyethylene resin trial production sample 5 is obtained, and the sample is treated to remove powder, and the performance is shown in Table 5. The evaluation results of the crystallization point of trial production sample 5 are shown in Figure 1 .

[0090] Table 5 Performance test results of trial production sample 5

[0091] project 5 pilot production samples Melt flow rate, g / 10min 3.0 Weight-average molecular weight, g / mol 61000 Molecular weight distribution index 3.4 Long branched chain content, ‰ 0.93 Zero-shear viscosity, Pa.s 6875 Powder content, ppm 22 Total number of crystal points, pieces / m 2 ]] 0.30

[0092] The value calculated according to 0.12709x1+2.57189x10 7 x2-24802.3 for trial production sample 5 is 6869, and the measured value of zero shear viscosity y is 6875, which meets the specific relationship (y≥0.12709x1+2.57189x10 7 x2-24802.3). When applied in downstream manufacturers, it can meet the requirements of electronic protection film.

[0093] Example 6

[0094] With ethylene as raw material, the amount of addition is 99.777g, the ethylene is pressurized to 270Mpa, the temperature is 168℃, the organic peroxide is used as initiator for polymerization reaction, the peroxide is added by four-point method, the peroxide is compounded by di-tert-butyl peroxide (DTBP), tert-butyl ethylhexanoate (TBPEH) and tert-butyl peroxypivalate (TBPPI), the peroxide ratio is DTBP:TBPEH:TBPPI is 10:5:2, the peroxide injection unit is diluted with organic solvent (isododecane) to the appropriate concentration of the above peroxide, that is, the mass concentration of organic peroxide in the four zones of the reactor is 13%, 6%, 6%, 4% respectively, the mass ratio of peroxide added in four zones is 13:6:6:4, the total amount of addition is 0.023g, the polymerization pressure is 266Mpa, the polymerization temperature is 289℃, the amount of propionaldehyde and butene-1 is adjusted to wt% (4:5), the amount of addition is 0.20g, first polyethylene is obtained, then it is extruded and granulated, the temperature of the extrusion granulator is 160℃, a high-pressure polyethylene resin trial production sample 6 is obtained, the performance is shown in Table 6.

[0095] Table 6 Performance test results of trial production sample 6

[0096] project Trial production sample 6 Melt flow rate, g / 10min 3.0 Weight-average molecular weight, g / mol 61000 Molecular weight distribution index 3.4 Long branched chain content, ‰ 0.93 Zero-shear viscosity, Pa.s 6875 Powder content, ppm 30 Total number of crystal points, pieces / m 2 ]] 0.5

[0097] The value calculated according to 0.12709x1+2.57189x10 7 7 x2-24802.3 of trial production sample 6 is 6869, the measured value y of zero shear viscosity is 6875, which meets the specific relationship (y≥0.12709x1+2.57189x10 7 x2-24802.3, and can meet the requirements of electronic protective film in downstream manufacturers.

[0098] Comparative example 1

[0099] With ethylene as raw material, the amount of addition is 99.76g, the ethylene is pressurized to 270Mpa, the temperature is 168℃, and the organic peroxide is used as the initiator for polymerization reaction. The peroxide is added in four points, and the peroxide is diluted to a suitable concentration by using an organic solvent (isododecane) in the peroxide injection unit. The mass concentration of the organic peroxide in the four zones is 13%, 6%, 6% and 4% respectively, and the mass ratio of the peroxide added in the four zones is 13:6:6:4. The total amount of addition is 0.040g. The organic peroxide is used as the initiator for polymerization reaction, the polymerization pressure is 268Mpa, the polymerization temperature is 302℃, the amount of addition of propionaldehyde and butene-1 is wt% (4:5), and the amount of addition is 0.20g. The polyethylene resin test sample 1 is obtained by extruding and granulating, and the temperature of the extruding and granulating machine is 175℃. The sample is treated by de-dusting, and the performance is shown in Table 7. The evaluation results of the crystal point of the test sample 1 are shown in Table 8. Figure 2

[0100] Table 7 Performance test results of the test sample 1

[0101] project Comparison Sample 1 Melt flow rate, g / 10min 3.0 Weight-average molecular weight, g / mol 64000 Molecular weight distribution index 4.0 Long branched chain content, ‰ 0.97 Zero-shear viscosity, Pa.s 6800 Powder content, ppm 22 Total number of crystal points, pieces / m 2 ]] 0.83

[0102] The test sample 1 is applied in a downstream factory, and the calculated value according to 0.12709x1+2.57189x10 7 x2-24802.3 is 8278, and the measured value of the zero shear viscosity y is 6800, which does not meet the specific relationship (y≥0.12709x1+2.57189x10 7 x2-24802.3). The crystal point test is performed by using the SCD-50 type crystal point instrument of the Harp company, and the results show that the total number of crystal points of the test sample 1 is high. The test sample 1 cannot meet the requirements of the electronic protective film when it is applied in the downstream factory.

[0103] Comparing the test sample 1 with Figure 1 and Figure 2 , it can be seen that the total number of crystal points and the size of the crystal points of the test sample 1 are higher than those of the test production sample 5.

[0104] Comparative example 2

[0105] ​With ethylene as raw material, the adding amount is 99.86g, the ethylene is pressurized to 262Mpa, the temperature is 175℃, and the organic peroxide is used as an initiator to carry out the polymerization reaction, the peroxide is added in four points, the diter-butyl peroxide (DTBP), t-butyl hexanoate (TBPIN), t-butyl ethylhexanoate (TBPEH) and t-butyl peroxide pivalate (TBPPI) are compounded, the mass ratio of the peroxides is 1:2:2:2, the peroxide injection unit is diluted with an organic solvent (isododecane) to a suitable concentration, that is, the mass concentration of the organic peroxide in the four zones of the reactor is 16wt%, 9wt%, 7wt% and 7wt% respectively, the mass ratio of the peroxides added in the four zones is 16:9:7:7, the total adding amount is 0.02g, the organic peroxide is used as an initiator to carry out the polymerization reaction, the polymerization pressure is 268Mpa, the polymerization temperature is 288.5℃, the adjusting propyl aldehyde and butene-1 amount wt% (7:3) is 0.12g, the polyethylene is obtained first, the temperature of the extrusion granulator is 190℃, the polyethylene resin comparative sample 2 is obtained, and the sample is subjected to the powder removal treatment, and the performance is shown in Table 8.

[0106] Table 8 performance test results of comparative sample 2

[0107] project Comparison Sample 2 Melt flow rate, g / 10min 2.009 Weight-average molecular weight, g / mol 66000 Molecular weight distribution index 3.3 Long branched chain content, ‰ 1.0 Zero-shear viscosity, Pa.s 8000 Powder content, ppm 22 Total number of crystal points, pieces / m 2 ]] 0.59

[0108] The value calculated according to 0.12709x1+2.57189x10 7 2-24802.3 of comparative sample 2 is 9304.54, the zero shear viscosity measured value y is 8000, which does not meet the specific relationship (y≥0.12709x1+2.57189x10 7 2-24802.3), because the temperature of the extrusion granulator is high, the molecular chain is further reacted under the action of the residual initiator in the granulation stage, the molecular weight distribution index of the obtained polyethylene resin is wide, the content of the macromolecule is high, and then the total number of the crystal points of the electronic protection film prepared from the polyethylene resin is more, therefore, the electronic protection film cannot meet the requirements.

[0109] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. A polyethylene resin for an electronic protection film, characterized by, The weight average molecular weight of the polyethylene resin is denoted as x1, the long chain branch content is denoted as x2, and the zero shear viscosity is denoted as y, x1, x2, and y satisfy the following relationship: y ≥ 0.12709x1+ 2.57189x2- 24802.3 7 x2-24802.3; The weight average molecular weight x1 of the polyethylene resin ranges from 55000 to 75000 g / mol, the long chain branch content x2 of the polyethylene resin is less than or equal to 0.95 ‰, and the molecular weight distribution index of the polyethylene resin ranges from 3.0 to 3.

8. The preparation method of the polyethylene resin for electronic protective film comprises the following steps: Step 1: ethylene is pressurized to 260-270 MPa and heated to 165-168 ℃, and then introduced into a reactor to perform a polymerization reaction under the initiation of an organic peroxide to obtain polyethylene; Step 2: the polyethylene obtained in step 1 is extruded and granulated, and the barrel temperature of the extruder is 140-170 ℃ to obtain a polyethylene resin. The pressure of the polymerization reaction is 265-275 MPa, and the temperature of the polymerization reaction is 280-289 ℃.

2. The polyethylene resin for electronic protection films according to claim 1, characterized by The powder content of the polyethylene resin is less than or equal to 30 ppm.

3. The electronic protection film prepared from the polyethylene resin of claim 1 or 2, characterized in that, The electronic protective film has crystal points ≤ 0.5 / m 2 , crystal point size ≤ 500 microns.

4. A method for producing a polyethylene resin for an electronic protection film, characterized by comprising the steps of: The preparation method of the polyethylene resin for electronic protective film comprises the following steps: Step 1: ethylene is pressurized to 260-270 MPa and heated to 165-168 ℃, and then introduced into a reactor to perform a polymerization reaction under the initiation of an organic peroxide to obtain polyethylene; Step 2: the polyethylene obtained in step 1 is extruded and granulated, and the barrel temperature of the extruder is 140-170 ℃ to obtain a polyethylene resin. The pressure of the polymerization reaction is 265-275 MPa, and the temperature of the polymerization reaction is 280-289 ℃.

5. The method of making a polyethylene resin for electronic protection films according to claim 4, characterized in that, The organic peroxide is diluted with isododecane before being added to the reactor to obtain a diluted organic peroxide, and the mass concentration of the organic peroxide in the diluted organic peroxide is 5%-20%; the organic peroxide is 2-ethylhexyl peroxydicarbonate, di-t-butyl peroxide, t-butyl peroxybenzoate, t-butyl peroxy-2-ethylhexanoate, t-butyl hexanoate, t-butyl ethylhexanoate, t-amyl ethylhexanoate, and t-butyl peroxypivalate.

6. The method of making a polyethylene resin for electronic protection films according to claim 5, characterized in that, The organic peroxide is diluted in an inert gas environment.

7. The method of making a polyethylene resin for electronic protection films according to claim 4, characterized in that, A molecular weight regulator is added during the polymerization reaction, the molecular weight regulator is at least one of propane, isobutane, acetone, propylene, isopropyl alcohol, butene-1, and propionaldehyde, and the addition amount of the molecular weight regulator is 0.05wt%-0.5wt% based on the total addition amount of ethylene, the organic peroxide, and the molecular weight regulator being 100%.

8. The method of making a polyethylene resin for electronic protection films according to claim 7, characterized in that, The addition amount of the organic peroxide is 0.01wt%-0.3wt% based on the total addition amount of ethylene, the organic peroxide, and the molecular weight regulator being 100%.

9. The method of making a polyethylene resin for electronic protection films according to claim 7, characterized in that, The molecular weight regulator is a mixture of propionaldehyde and butene-1, and the mass ratio of propionaldehyde to butene-1 is 7:3-3:7.

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