A protective film for a pipe rehabilitation lining hose and a method of manufacturing the same

Abstract

The application discloses a protective film for a pipeline repair lining hose, which is a co-extrusion film. The co-extrusion film comprises a first visible light resistant surface layer, a bonding layer, a barrier core layer, a bonding layer, an ultraviolet resistant layer and a second visible light resistant surface layer which are stacked in sequence. The main components of the first visible light resistant surface layer and the second visible light resistant surface layer are mLLDPE, LLDPE, LDPE and a visible light resistant master batch. The ultraviolet resistant layer comprises at least one unit layer, and the main components of the unit layer are LLDPE, LDPE and an ultraviolet resistant master batch, or LDPE and an ultraviolet resistant master batch. In the structure of the protective film for the pipeline repair lining hose, the first visible light resistant surface layer and the second visible light resistant surface layer can resist visible light and block the light transmittance of ultraviolet rays, and the ultraviolet resistant layer cooperates with the first visible light resistant surface layer and the second visible light resistant surface layer to improve the ultraviolet resistant effect of the protective film, effectively improve the service life of the protective film and prolong the timeliness of the ultraviolet resistant protective film.

Description

Technical Field

[0001] This invention relates to the field of membrane technology for pipeline repair, specifically to a protective membrane for pipeline repair lining hoses and its preparation method. Background Technology

[0002] As urban sewer pipes age, the probability of damage or collapse increases, potentially affecting public safety and convenience. Traditional pipe repair methods involve excavation and repair, which are extensive and significantly impact the orderly operation of the city.

[0003] Trenchless pipeline repair has been increasingly widely applied in my country in recent years. The processes of trenchless pipeline repair can be broadly classified into four categories: the first is cured-in-place pipe (CIPP), the second is the insertion method, and the third, mainly represented by spiral pipe fabrication and spraying, are also methods. In the first category, CIPP, a new pipe is formed inside the old pipe after the fiber-impregnated resin-coated hose has been cured. However, the UV-cured hose is exposed to sunlight and ultraviolet radiation during transportation, causing premature curing and hose failure. Therefore, a UV-protective film needs to be applied to the outer surface of the UV-cured hose. Existing UV-protective films, after a period of use, show UV inhibitors leaching or becoming ineffective, leading to a shortened lifespan or rendering the resin-impregnated hose unusable.

[0004] Therefore, it is necessary to improve the protective film used for lining hoses in pipeline repair in the existing technology. Summary of the Invention

[0005] One of the objectives of this invention is to overcome the deficiencies in the prior art and provide a protective film for pipe repair lining hoses. This protective film has good resistance to both visible and ultraviolet light, high stability, and extends the service life and effectiveness of its resistance to visible and ultraviolet light.

[0006] To achieve the above-mentioned process effects, the technical solution of the present invention is as follows: a protective film for pipe repair lining hose, which is a co-extruded film, the co-extruded film comprising a first anti-light surface layer, an adhesive layer, a barrier core layer, an adhesive layer, an anti-ultraviolet layer and a second anti-light surface layer stacked in sequence;

[0007] The main components of the first and second anti-light coatings are mLLDPE, LLDPE, LDPE and anti-light masterbatch;

[0008] The UV-resistant layer includes at least one unit layer, the main components of which are LLDPE, LDPE and UV-resistant masterbatch, or LDPE and UV-resistant masterbatch.

[0009] The preferred technical solution is as follows: the UV-resistant layer includes at least two unit layers, the UV-resistant layer includes a first unit layer and a second unit layer, and an anti-light layer is sandwiched between the first unit layer and the second unit layer;

[0010] Alternatively, the UV-resistant layer may comprise a first unit layer, a third unit layer, and a second unit layer that are sequentially composited.

[0011] The first unit layer is connected to the second anti-light surface layer.

[0012] The preferred technical solution is as follows: based on the mass of the first anti-light surface layer being 100%, the main components of the first anti-light surface layer are 25% to 35% LLDPE, 40% to 50% LLDPE, 10% to 15% LDPE and 10% to 20% anti-light masterbatch;

[0013] Based on the mass of the second anti-light coating being 100%, the main components of the second anti-light coating are 25%–35% LLDPE, 40%–50% LLDPE, 10%–20% LDPE, and 5%–10% anti-light masterbatch.

[0014] Furthermore, based on the mass of the first anti-light surface layer being 100%, the main components of the first anti-light surface layer are 28%–35% mLLDPE, 40%–50% LLDPE, 10%–15% LDPE, and 12%–18% anti-light masterbatch;

[0015] Based on the mass of the second anti-light coating being 100%, the main components of the second anti-light coating are 28%–35% LLDPE, 40%–48% LLDPE, 10%–18% LDPE, and 5%–8% anti-light masterbatch.

[0016] Furthermore, based on the mass of the first anti-light surface layer being 100%, the main components of the first anti-light surface layer are 28%–33% LLDPE, 42%–47% LLDPE, 10%–15% LDPE, and 15%–18% anti-light masterbatch;

[0017] Based on the mass of the second anti-light coating being 100%, the main components of the second anti-light coating are 30%–35% LLDPE, 40%–47% LLDPE, 10%–18% LDPE, and 5%–8% anti-light masterbatch.

[0018] The preferred technical solution is as follows: based on the mass of the first unit layer being 100%, the main components of the first unit layer are 70% to 80% LLDPE, 15% to 25% LDPE, and 4% to 8% UV-resistant masterbatch;

[0019] Based on the mass of the second unit layer being 100%, the main components of the second unit layer are 91%–95% LDPE and 5%–9% UV-resistant masterbatch;

[0020] Based on the mass of the anti-light layer being 100%, the main components of the anti-light layer are 70%–80% LLDPE, 15%–25% LDPE, and 5%–10% anti-light masterbatch;

[0021] Based on the mass of the third unit layer being 100%, the main components of the third unit layer are 90%–95% LDPE and 5%–10% UV-resistant masterbatch.

[0022] Furthermore, based on the mass of the first unit layer being 100%, the main components of the first unit layer are 72%–80% LLDPE, 15%–22% LDPE, and 4%–8% UV-resistant masterbatch;

[0023] Based on the second unit layer having a mass of 100%, the main components of the second unit layer are 92%–95% LDPE and 5%–8% UV-resistant masterbatch;

[0024] Based on the mass of the anti-light layer being 100%, the main components of the anti-light layer are 72%–78% LLDPE, 16%–22% LDPE, and 6%–10% anti-light masterbatch;

[0025] Based on the mass of the third unit layer being 100%, the main components of the third unit layer are 90%–94% LDPE and 6%–10% UV-resistant masterbatch.

[0026] The preferred technical solution is that the anti-light masterbatch is model BSM50667; and the anti-ultraviolet masterbatch is model TGN115.

[0027] The preferred technical solution is that the thickness of the UV-resistant layer accounts for 15% to 27% of the total thickness of the co-extruded film, and the thickness ratio of the first unit layer, the UV-resistant layer, and the second unit layer is 1:

[0028] (0.9~1.1): (0.7~1.1);

[0029] Alternatively, the UV-resistant layer may comprise a first unit layer, a third unit layer, and a second unit layer, which are sequentially composited in a layer thickness ratio of 1:(0.9~1.1):(0.7~0.9).

[0030] Furthermore, the thickness of the UV-resistant layer accounts for 20% to 27% of the total thickness of the co-extruded film, and the thickness ratio of the first unit layer, the UV-resistant layer, and the second unit layer is 1:(0.9 to 1):(0.8 to 1.1).

[0031] Alternatively, the UV-resistant layer may consist of a first unit layer, a third unit layer, and a second unit layer, which are sequentially composited with a layer thickness ratio of 1:(0.9~1.1):(0.7~0.8).

[0032] A preferred technical solution is as follows: the thickness of the first anti-light coating layer accounts for 25% to 35% of the total thickness of the co-extruded film, and the thickness of the second anti-light coating layer accounts for 5% to 10% of the total thickness of the co-extruded film. Further, the thickness of the first anti-light coating layer accounts for 27% to 35% of the total thickness of the co-extruded film, and the thickness of the second anti-light coating layer accounts for 6% to 9% of the total thickness of the co-extruded film.

[0033] A preferred technical solution is as follows: the barrier core layer comprises two barrier unit layers, wherein, based on 100% by weight, the main components of the barrier unit layers are 30%–50% homopolymer nylon and 50%–70% copolymer nylon. Further, the barrier core layer comprises two barrier unit layers, wherein, based on 100% by weight, the main components of the barrier unit layers are 40%–50% homopolymer nylon and 50%–60% copolymer nylon.

[0034] A preferred technical solution is that the adhesive layer is mainly composed of LLDPE and adhesive, and the mass ratio of LLDPE to adhesive is (1-4):1. Further, the adhesive layer is mainly composed of LLDPE and adhesive, and the mass ratio of LLDPE to adhesive is (2-3.5):1.

[0035] The second objective of this invention is to overcome the deficiencies in the prior art and provide a method for preparing a protective film for pipe repair lining hoses. The protective film for pipe repair lining hoses is as described above, wherein the extrusion feed temperature of the first anti-light surface layer is 210–220°C, and the die temperature is 210–220°C; the extrusion feed temperature of the barrier core layer is 245–255°C, and the die temperature is 245–255°C; the extrusion feed temperature of the unit layer is 210–220°C, and the die temperature is 210–220°C; the extrusion feed temperature of the second anti-light surface layer is 210–220°C, and the die temperature is 210–220°C; and the extrusion feed temperature of the adhesive layer is 220–230°C, and the die temperature is 220–230°C.

[0036] The advantages and beneficial effects of this invention are as follows:

[0037] 1. In the protective film structure for the inner lining hose of the pipeline repair, the first and second visible light-resistant surface layers can both resist visible light and block ultraviolet light transmittance. Together with the anti-ultraviolet layer, they improve the anti-ultraviolet effect of the protective film, effectively improve the service life of the protective film, and extend the anti-ultraviolet effect of the protective film.

[0038] 2. Compared to films containing only an anti-UV layer, to achieve the same anti-UV effect, the anti-UV layer is sandwiched between the first and second anti-visible light surface layers in a laminated structure. This reduces the amount of anti-UV masterbatch to be added, effectively improves the problem of anti-UV masterbatch precipitation, and also helps to enhance the mechanical properties of the film. Detailed Implementation

[0039] The specific embodiments of the present invention will be further described below with reference to examples. These examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0040] definition

[0041] In this disclosure, the term "PE" refers to polyethylene, which is a typical thermoplastic material and can be further subdivided into LDPE, LLDPE and HDPE.

[0042] In this disclosure, the term "LDPE" refers to low-density polyethylene.

[0043] In this disclosure, the term "LLDPE" refers to linear low-density polyethylene, which differs structurally from conventional low-density polyethylene because it lacks long branches.

[0044] In this disclosure, the term "mLLDPE" refers to a polymer produced by ethylene polymerization using a metallocene coordination compound as a catalyst.

[0045] In this disclosure, the term "COPA" refers to copolymer nylon, a polyamide obtained by polycondensation of multiple monomers, including random copolymerization, block copolymerization, and alternating copolymerization.

[0046] In this disclosure, the term "HOPA" refers to homopolymer nylon, a polyamide obtained by polycondensation of a monomer, which is a tough, angular, translucent or milky white crystalline resin.

[0047] model

[0048] The commercial brand name of the UV-resistant masterbatch is TGN115;

[0049] The commercial brand name of the anti-light masterbatch is BSM50667;

[0050] Metallocene linear low-density polyethylene is manufactured by ExxonMobil and its trade name is 1018MF.

[0051] Low-density polyethylene is manufactured by ExxonMobil, with the trade name HP0823JN;

[0052] Linear low-density polyethylene is manufactured by ExxonMobil and its trade name is 1002AY.

[0053] The linear low-density polyethylene is produced by SABIC, with the trade name 218NJ.

[0054] The linear low-density polyethylene is produced by SABIC, with the trade name 218WJ.

[0055] The adhesive was produced by Guangzhou Synthetic Co., Ltd., with the trade name HS3-405H3.

[0056] COPA is manufactured by Nantong Huafeng, and its brand name is HF2440B.

[0057] HOPA is manufactured by Nantong Huafeng, with the brand name HF1036B.

[0058] Protective film for lining hoses during pipe repair

[0059] The protective film is a multilayer co-extruded film, which may include, but is not limited to, seven-layer, nine-layer, or eleven-layer co-extruded films. Considering the outdoor usage conditions and the limitations of the production equipment itself, it is preferable that the co-extruded film has nine layers. The total thickness of the protective film is 180–250 μm.

[0060] Anti-light surface

[0061] The main components of the first and second anti-light coatings are mLLDPE, LLDPE, LDPE, and anti-light masterbatch. The more mLLDPE added, the greater the heat-sealing strength and the better the heat-sealing effect; too little added LLDPE reduces the mechanical strength of the film. Excessive LLDPE addition leads to processing difficulties and uneven dispersion of the anti-light masterbatch; insufficient addition increases the economic cost of the film and can cause the anti-light masterbatch to precipitate. The addition of LDPE effectively improves the processing performance of mLLDPE and the transparency of the film; excessive addition reduces the mechanical properties of the film, while insufficient addition leads to processing difficulties. Excessive addition of anti-light masterbatch reduces the mechanical properties of the film and increases costs; insufficient addition results in high light transmittance but reduced resistance to ultraviolet and visible light, leading to a shortened service life or rendering the resin-impregnated hose unusable after curing.

[0062] Excessive thickness of the first anti-light coating layer can cause film curling. With the total number of film layers remaining constant, insufficient thickness of the first anti-light coating layer increases the production pressure of other layers, and the increased light transmittance of the film has a negative impact on its UV resistance. With the total number of film layers remaining constant, excessive thickness of the second anti-light coating layer increases the production pressure of the barrier core layer and the UV-resistant layer. This is mainly because insufficient thickness is uncontrollable, resulting in poor mechanical strength of the film and a negative impact on its UV resistance. Insufficient thickness increases the light transmittance of the coating layer, weakening its synergistic effect with the UV-resistant layer, and negatively impacting both UV and visible light resistance.

[0063] UV protection layer

[0064] The UV-resistant layer comprises a first unit layer, an anti-light layer, and a second unit layer, which are sequentially composited.

[0065] The first unit layer further prevents the precipitation of UV-resistant masterbatch and improves the UV resistance stability of the film. LLDPE, the main component of the first unit layer, effectively prevents the precipitation of added UV-resistant masterbatch. When mixed with LDPE, it improves the dispersion uniformity of the UV-resistant masterbatch and works synergistically with the second anti-light surface layer, thereby improving the film's UV and visible light resistance. Excessive LDPE addition reduces the film's mechanical properties, while insufficient addition hinders processing of this layer. Excessive UV-resistant masterbatch addition leads to material waste, increased costs, and decreased mechanical properties of the film, while insufficient addition results in poor UV resistance.

[0066] The second unit layer primarily improves the continuity and enhancement of UV resistance, and also enables the production of a thin and lightweight film. Excessive LDPE addition will reduce the film's UV resistance and mechanical properties, while insufficient addition will lead to uneven dispersion of the UV masterbatch and waste of the UV masterbatch material.

[0067] The anti-light layer is sandwiched between the first and second unit layers, and works synergistically with the anti-UV layer and the second anti-light surface layer to improve the film's resistance to UV and visible light and extend the duration of its UV and visible light resistance. LLDPE effectively prevents the precipitation of the added anti-light masterbatch, and mixing it with LDPE improves the dispersion uniformity of the anti-light masterbatch.

[0068] Both excessively thick and insufficiently thin first and second unit layers are difficult to process, due to limitations imposed by the equipment itself and the structure and performance of adjacent layers. Excessive or insufficient thickness of the first and second unit layers negatively impacts the film's stability, rigidity, and toughness. Excessive thickness of the anti-light layer negatively affects the UV resistance of the anti-UV layer, while insufficient thickness leads to poor film stability.

[0069] The UV-resistant layer comprises a first unit layer, a third unit layer, and a second unit layer that are sequentially composited. The first unit layer, the third unit layer, and the second unit layer are combined and work synergistically with the second visible light resistant surface layer to improve the film's UV and visible light resistance, extend the duration of UV and visible light resistance, and effectively solve the problem of UV masterbatch precipitation.

[0070] The combination of the third unit layer with the first and second unit layers not only improves the UV resistance of the film, but also aims to obtain a thinner film and improve economic efficiency.

[0071] Barrier Core

[0072] It includes two barrier unit layers, in which homopolymer nylon and copolymer nylon are blended. This is more economical and improves the processability of the barrier layer and the rigidity and toughness of the film. While using only homopolymer nylon can improve barrier performance, it presents processing difficulties for films with large thickness and width requirements.

[0073] Example 1

[0074] The protective film for the inner lining hose of the pipeline repair is a nine-layer co-extruded film structure. The co-extruded film includes a first light-resistant surface layer, an adhesive layer, a barrier core layer, an adhesive layer, an anti-ultraviolet layer, and a second light-resistant surface layer stacked in sequence. The anti-ultraviolet layer includes a first unit layer, an anti-ultraviolet layer, and a second unit layer that are stacked in sequence. The first unit layer is connected to the second light-resistant surface layer, and the second unit layer is connected to the barrier core layer through the adhesive layer.

[0075] The first anti-light surface layer is bonded to the inner lining tube. Based on 100% of the raw material weight of the film layer, the raw material composition of the nine co-extruded film layers from the outside to the inside is as follows:

[0076] A: 32% Exceed MLLDPE1018MF, 44% LLDPE218WJ, 16% SABIC LDPEHP0823JN, and 8% anti-light masterbatch; corresponding to the second anti-light surface layer.

[0077] B: 75% LLDPE1002AY, 18% SABIC LDPE HP0823JN, and 7% UV-resistant masterbatch; corresponding to the first unit layer.

[0078] C: 75% LLDPE1002AY, 17% SABIC LDPE HP0823JN, 8% anti-light masterbatch; corresponding anti-light layer.

[0079] D: 93% SABIC LDPE HP0823JN, 7% UV-resistant masterbatch; corresponding to the second unit layer.

[0080] E: 75% LLDPE218NJ, 25% adhesive HS3-405H3;

[0081] F: 45% HF2440B, 65% HF1036B; corresponding to the barrier cell layer.

[0082] G: 45% HF2440B, 65% HF1036B; corresponding to the barrier cell layer.

[0083] H: 75% LLDPE218NJ, 25% adhesive HS3-405H3;

[0084] J: 30% Exceed MLLDPE1018MF, 42% LLDPE218WJ, 12% SABIC LDPEHP0823JN, and 16% anti-light masterbatch. Corresponds to the first anti-light surface layer.

[0085] The above raw materials are fed into the corresponding extrusion mechanism of the co-extrusion film production equipment. The co-extruded film is discharged through the die head, and the thickness of the co-extruded film is 200μm. Among them, the thickness of layer A is 14μm; the thickness of layer B is 17μm; the thickness of layer C is 16μm; the thickness of layer D is 17μm; the thickness of layer E is 14μm; the thickness of layer F is 24μm; the thickness of layer G is 24μm; the thickness of layer H is 14μm; and the thickness of layer J is 60μm.

[0086] The extrusion temperatures of layers A through J in the co-extrusion equipment, in the order of feeding section, plasticizing section, homogenizing section, extrusion section, and die head, are as follows:

[0087] A: 180℃—215℃—215℃—215℃—215℃;

[0088] B: 180℃—215℃—215℃—215℃—215℃;

[0089] C: 180℃—215℃—215℃—215℃—215℃;

[0090] D: 180℃—215℃—215℃—215℃—215℃;

[0091] E: 225℃—225℃—225℃—225℃—225℃;

[0092] F: 250℃—250℃—250℃—250℃—250℃;

[0093] G: 250℃—250℃—250℃—250℃—250℃;

[0094] H: 225℃—225℃—225℃—225℃—225℃;

[0095] J: 180℃—215℃—215℃—215℃—215℃.

[0096] Example 2

[0097] Example 2 is based on Example 1, except that the UV-resistant layer comprises a first unit layer, a third unit layer, and a second unit layer sequentially laminated together. The first unit layer is connected to the second UV-resistant surface layer, and the second unit layer is connected to the barrier core layer via an adhesive layer.

[0098] A1: 32% Exceed MLLDPE1018MF, 44% LLDPE218WJ, 16% SABIC LDPEHP0823JN, and 8% anti-light masterbatch; corresponding to the second anti-light surface layer.

[0099] B1: 75% LLDPE1002AY, 18% SABIC LDPE HP0823JN, and 7% UV-resistant masterbatch; corresponding to the first unit layer.

[0100] C1: 91% SABIC LDPE HP0823JN, 9% UV-resistant masterbatch; corresponding to the third unit layer.

[0101] D1: 93% SABIC LDPE HP0823JN, 7% UV-resistant masterbatch; corresponding to the second unit layer.

[0102] E1: 75% LLDPE218NJ, 25% adhesive HS3-405H3;

[0103] F1: 45% HF2440B, 65% HF1036B; corresponding to the barrier cell layer.

[0104] G1: 45% HF2440B, 65% HF1036B; corresponding to the barrier cell layer.

[0105] H1: 75% LLDPE218NJ, 25% adhesive HS3-405H3;

[0106] J1: 30% Exceed MLLDPE1018MF, 42% LLDPE218WJ, 12% SABIC LDPEHP0823JN, and 16% anti-light masterbatch. Corresponds to the first anti-light surface layer.

[0107] The above raw materials are fed into the corresponding extrusion mechanism of the co-extrusion film production equipment. The co-extruded film is discharged through the die head, and the thickness of the co-extruded film is 200μm. Among them, the thickness of layer A1 is 14μm; the thickness of layer B1 is 18μm; the thickness of layer C1 is 18μm; the thickness of layer D1 is 14μm; the thickness of layer E1 is 14μm; the thickness of layer F1 is 24μm; the thickness of layer G1 is 24μm; the thickness of layer H1 is 14μm; and the thickness of layer J1 is 60μm.

[0108] The extrusion temperatures of layers A1 to J1 in the co-extrusion equipment, in the order of feeding section, plasticizing section, homogenizing section, extrusion section, and die head, are as follows:

[0109] A1: 180℃—215℃—215℃—215℃—215℃;

[0110] B1: 180℃—215℃—215℃—215℃—215℃;

[0111] C1: 180℃—215℃—215℃—215℃—215℃;

[0112] D1: 180℃—215℃—215℃—215℃—215℃;

[0113] E1: 225℃—225℃—225℃—225℃—225℃;

[0114] F1: 250℃—250℃—250℃—250℃—250℃;

[0115] G1: 250℃—250℃—250℃—250℃—250℃;

[0116] H1: 225℃—225℃—225℃—225℃—225℃;

[0117] J1: 180℃—215℃—215℃—215℃—215℃.

[0118] Example 3

[0119] Example 3 is based on Example 2, except that the UV-resistant layer consists of only one unit layer, which is composed of 75% LLDPE1002AY, 18% SABIC LDPE HP0823JN, and 7% UV-resistant masterbatch. The thicknesses of the first UV-resistant surface layer, adhesive layer, barrier core layer, adhesive layer, and second UV-resistant surface layer remain unchanged, and the thickness of this unit layer is 50 μm.

[0120] Comparative Example 1

[0121] Comparative Example 1 is based on Example 1, except that the second anti-light coating does not contain anti-light masterbatch, namely A: 32% Exceed MLLDPE1018MF, 48% LLDPE218WJ, and 20% SABIC LDPE HP0823JN. The composition of the other layers remains unchanged, as do the total film thickness, the thickness of each layer, and the processing technology.

[0122] Comparative Example 2

[0123] Comparative Example 2 is based on Example 1, except that the first anti-light coating does not contain anti-light masterbatch, i.e., J: 35% Exceed MLLDPE1018MF, 50% LLDPE218WJ, and 15% SABIC LDPE HP0823JN. The composition of the other layers remains unchanged, as do the total film thickness, the thickness of each layer, and the processing technology.

[0124] Comparative Example 3

[0125] Comparative Example 3 is based on Example 1, except that the second anti-light coating contains anti-light masterbatch and anti-UV masterbatch, and the total mass of the anti-light masterbatch and anti-UV masterbatch accounts for 8% of the mass of the raw materials of the second anti-light coating. The mass ratio of the anti-light masterbatch and the anti-UV masterbatch is 1:1.

[0126] Comparative Example 4

[0127] Comparative Example 4 is based on Example 1, except that neither the first nor the second anti-light coating contains anti-light masterbatch. The first anti-light coating does not contain anti-light masterbatch, namely J: 35% Exceed MLLDPE1018MF, 50% LLDPE218WJ, and 15% SABIC LDPE HP0823JN; the second anti-light coating does not contain anti-light masterbatch, namely A: 32% Exceed MLLDPE1018MF, 48% LLDPE218WJ, and 20% SABIC LDPE HP0823JN. The composition of the other layers remains unchanged, as does the total film thickness, the thickness of each layer, and the processing technology.

[0128] Test methods for the sample:

[0129] 1. Tensile strength and elongation at break determination: according to test standard GB / T1040.3-2006;

[0130] 2. Water vapor transmission rate determination: according to test standard GB / T1037-1988;

[0131] 3. Oxygen permeability determination: according to test standard GB / T1038-2000;

[0132] 4. UV resistance test: The protective film is heat-sealed into a 20*20cm packaging bag, which contains UV-curable adhesive. If the adhesive does not cure after 24 hours of outdoor exposure, the UV resistance is excellent and is marked OK; otherwise, it does not have UV resistance and is marked NG.

[0133] 5. Duration test of UV resistance: The packaging bag with a specification of 20*20cm contains UV-curing adhesive and is placed outdoors for a cumulative period of no less than 900 hours of sunlight.

[0134] The UV-curable adhesive is a mixture of isophenylene neopentyl glycol type unsaturated polyester resin 2855-ED and magnesium oxide paste 2030-25.

[0135]

[0136] Example 1 and Example 2 have similar performance, but the protective film of Example 2 is lighter for the same total film thickness.

[0137] The second anti-light coating of the protective film obtained in Comparative Example 3 showed uneven mixing of the anti-light masterbatch and the anti-UV masterbatch, resulting in poor appearance and quality of the finished product.

[0138] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A protective film for lining flexible hoses used in pipe repair, which is a co-extruded film, characterized in that, The co-extruded film comprises a first anti-light surface layer, an adhesive layer, a barrier core layer, an adhesive layer, an anti-ultraviolet layer, and a second anti-light surface layer, which are stacked sequentially. Based on the mass of the first anti-light coating layer being 100%, the main components of the first anti-light coating layer are 25%~35% LLDPE, 40%~50% LLDPE, 10%~15% LDPE, and 10%~20% anti-light masterbatch; Based on the mass of the second anti-light coating being 100%, the main components of the second anti-light coating are 25%~35% LLDPE, 40%~50% LLDPE, 10%~20% LDPE, and 5%~10% anti-light masterbatch; The UV-resistant layer includes at least two unit layers, including a first unit layer and a second unit layer, with an anti-light layer sandwiched between the first unit layer and the second unit layer; Alternatively, the UV-resistant layer may comprise a first unit layer, a third unit layer, and a second unit layer that are sequentially composited. The first unit layer is connected to the second anti-light surface layer; Based on the mass of the first unit layer being 100%, the main components of the first unit layer are 70%~80% LLDPE, 15%~25% LDPE, and 4%~8% UV-resistant masterbatch; Based on the second unit layer having a mass of 100%, the main components of the second unit layer are 91%~95% LDPE and 5%~9% UV-resistant masterbatch; Based on the mass of the anti-light layer being 100%, the main components of the anti-light layer are 70%~80% LLDPE, 15%~25% LDPE, and 5%~10% anti-light masterbatch; Based on the mass of the third unit layer being 100%, the main components of the third unit layer are 90%~95% LDPE and 5%~10% UV-resistant masterbatch.

2. The protective film for pipe repair lining hoses according to claim 1, characterized in that, The anti-light masterbatch is model BSM50667; the anti-UV masterbatch is model TGN115.

3. The protective film for pipe repair lining hoses according to claim 1, characterized in that, The thickness of the UV-resistant layer accounts for 15% to 27% of the total thickness of the co-extruded film, and the thickness ratio of the first unit layer, the UV-resistant layer, and the second unit layer is 1:(0.9~1.1):(0.7~1.1). Alternatively, the UV-resistant layer may consist of a first unit layer, a third unit layer, and a second unit layer, which are sequentially composited in a layer thickness ratio of 1:(0.9~1.1):(0.7~0.9).

4. The protective film for pipe repair lining hoses according to claim 1 or 3, characterized in that, The thickness of the first anti-light coating layer accounts for 25% to 35% of the total thickness of the co-extruded film, and the thickness of the second anti-light coating layer accounts for 5% to 10% of the total thickness of the co-extruded film.

5. The protective film for pipe repair lining hoses according to claim 1, characterized in that, The barrier core layer comprises two barrier unit layers. Based on the mass of the barrier unit layer being 100%, the main components of the barrier unit layer are 30% to 50% homopolymer nylon and 50% to 70% copolymer nylon.

6. The protective film for pipe repair lining hoses according to claim 1, characterized in that, The adhesive layer is mainly composed of LLDPE and adhesive, and the mass ratio of LLDPE to adhesive is (1~4):

1.

7. A method for preparing a protective film for a pipe repair lining hose, characterized in that, The protective film for pipe repair lining hoses is the protective film for pipe repair lining hoses as described in any one of claims 1 to 6, wherein the extrusion feed temperature of the first anti-light surface layer is 210~220℃, and the die temperature is 210~220℃; the extrusion feed temperature of the barrier core layer is 245~255℃, and the die temperature is 245~255℃; the extrusion feed temperature of the unit layer is 210~220℃, and the die temperature is 210~220℃; the extrusion feed temperature of the second anti-light surface layer is 210~220℃, and the die temperature is 210~220℃; and the extrusion feed temperature of the adhesive layer is 220~230℃, and the die temperature is 220~230℃.

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