A high-cold-resistance waterproof board for tunnels and a preparation method thereof

Abstract

The application relates to the technical field of railway engineering building materials, in particular to a high-cold-resistance waterproof plate for a tunnel and a preparation method thereof. The waterproof plate is prepared from an upper layer of a metallocene-polyolefin mixture with a mass ratio of (13-17):60:(23-27), a middle layer of polyester short fiber reinforced polyolefin and a lower layer of modified polyolefin. The raw materials of the polyester short fiber reinforced polyolefin in the middle layer include the following components in parts by weight: linear low-density polyethylene 25-35 parts, thermoplastic polyolefin 5-10 parts, modified polyester short fiber 3-5 parts, polyethylene wax 1-3 parts, white carbon black 3-6 parts, cold-resistance toughening agent 2-4 parts, antioxidant 1-3 parts and ultraviolet resistance agent 1-3 parts. The length of the modified polyester short fiber is 3-6 mm, the modified polyester short fiber is a polyester short fiber treated by a silane coupling agent, and the cold-resistance toughening agent is a maleic anhydride graft copolymer. The waterproof plate can still maintain good mechanical properties and flexibility at low temperatures and is suitable for low-temperature environments.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of railway engineering building materials, in particular to a high-cold-resistance waterproof plate for tunnels and a preparation method thereof. BACKGROUND

[0002] At present, the commonly used waterproof plates for railway tunnels mainly include high-molecular waterproof coiled materials, such as polyethylene (PE) waterproof plates and polyvinyl chloride (PVC) waterproof plates. These waterproof plates have certain waterproof performance and physical and mechanical properties, and meet the basic requirements of railway tunnel waterproofing to a certain extent.

[0003] However, in cold regions, railway tunnels are faced with extremely low temperature conditions. In a low-temperature environment, the molecular chain movement of the existing waterproof plates is slowed down, and the flexibility and elasticity are significantly reduced, becoming hard and brittle. This makes the waterproof plates prone to cracking and breaking when subjected to external forces such as expansion and contraction deformation of the tunnel structure due to temperature changes, surrounding rock pressure, etc., thereby damaging the integrity of the waterproof plates and causing the waterproof function to fail. For example, in the railway tunnels in the northeast of China and the high-cold regions such as the Qinghai-Tibet Plateau, the waterproof plates often crack and leak in winter, which poses a serious threat to the safe operation of the tunnels. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a high-cold-resistance waterproof plate for tunnels and a preparation method thereof.

[0005] To solve the above problems, the technical solution adopted by the present application is as follows:

[0006] In a first aspect, a high-cold-resistance waterproof plate for tunnels is provided, which is prepared from an upper layer of a metallocene-polyolefin mixture with a mass ratio of (13-17):60:(23-27), a middle layer of polyester short fiber reinforced polyolefin, and a lower layer of modified polyolefin.

[0007] The raw materials of the middle layer of polyester short fiber reinforced polyolefin include, in terms of weight parts, linear low-density polyethylene 25-35 parts, thermoplastic polyolefin 5-10 parts, modified polyester short fiber 3-5 parts, polyethylene wax 1-3 parts, white carbon black 3-6 parts, cold-resistant toughening agent 2-4 parts, antioxidant 1-3 parts, and ultraviolet resistance agent 1-3 parts.

[0008] The length of the modified polyester short fiber is 3-6 mm, and it is a polyester short fiber treated with a silane coupling agent. The cold-resistant toughening agent is a maleic anhydride grafted copolymer.

[0009] As an embodiment of the present application, the raw materials of the upper layer metallocene-polyolefin mixture include, in parts by weight, polyolefin elastomer POE 2~4 parts, metallocene polyethylene 20~30 parts, high-density polyethylene 20~30 parts, antioxidant 1~3 parts, and ultraviolet inhibitor 1~3 parts.

[0010] As an embodiment of the present application, the raw materials of the lower layer modified polyolefin include, in parts by weight, ethylene-vinyl acetate copolymer 10~15 parts, linear low-density polyethylene 20~35 parts, high-density polyethylene 20~35 parts, antioxidant 1~3 parts, and ultraviolet inhibitor 1~3 parts.

[0011] As an embodiment of the present application, the antioxidant is selected from at least one of phenolic antioxidant and amine antioxidant; and the ultraviolet inhibitor is selected from at least one of UV-327, UV-531, and UV-326.

[0012] As an embodiment of the present application, the preparation method of the middle layer polyester short fiber reinforced polyolefin includes:

[0013] Step S201, uniformly mixing linear low-density polyethylene, thermoplastic polyolefin, polyethylene wax, white carbon black, cold-resistant toughening agent, antioxidant, and ultraviolet inhibitor;

[0014] Step S202, pouring the mixed middle layer material of step S201 into a main feeding hopper, pouring modified polyester short fiber into a side feeding hopper, and then extruding, drawing, and granulating through a double-screw granulator to prepare the middle layer polyester short fiber reinforced polyolefin.

[0015] As an embodiment of the present application, the preparation method of the modified polyester short fiber includes:

[0016] (1) Polyester short fiber pretreatment: placing polyester short fiber in a deionized water solution containing 0.5%~2% sodium dodecyl benzene sulfonate, stirring at 50~60℃ for 30~60 min, and then drying; the drying temperature is 80~100℃, and the drying time is 2~4 h; wherein the ratio of polyester short fiber to deionized water solution is 1 kg:(10~15) L;

[0017] (2) Preparing a hydrolysis solution containing active silicon alcohol groups: adding γ-aminopropyl triethoxysilane into ethanol to prepare a mixed solution with a mass fraction of 0.5%~5%; adding deionized water equivalent to 5~20% of the mass of the γ-aminopropyl triethoxysilane to the mixed solution, adjusting the pH value to 4~5, and then stirring at room temperature for 0.8~1.2 h to obtain the hydrolysis solution;

[0018] (3) preparing modified polyester staple fiber: adding the pretreated polyester staple fiber into the hydrolysis solution, stirring at a stirring speed of 100-300 r / min at room temperature for 30-120 min, and then filtering, washing, and drying to obtain the modified polyester staple fiber.

[0019] As an embodiment of the present application, the thickness of the high cold-resistant waterproof plate for tunnel is 1.5-2 mm.

[0020] In a second aspect, a preparation method of the high cold-resistant waterproof plate for tunnel is provided, and the method comprises the following steps:

[0021] The upper layer of metallocene-polyolefin mixture, the middle layer of polyester staple fiber reinforced polyolefin, and the lower layer of modified polyolefin are respectively added into corresponding hoppers, extruded by a three-layer co-extrusion equipment, and then cooled and calendered to obtain the high cold-resistant waterproof plate for tunnel.

[0022] The screw temperature of the co-extrusion equipment is 200-220℃, the die temperature is 210-230℃, the screw rotation speed is 280-320 r / min, and the coating machine roller temperature is 10-30℃.

[0023] As an embodiment of the present application, the upper layer of metallocene-polyolefin mixture and the lower layer of modified polyolefin are obtained by uniformly mixing all raw materials, extruding by a double-screw granulator, drawing, and cutting.

[0024] The screw temperature of the double-screw granulator is 190-210℃, the die temperature is 200-220℃, and the screw rotation speed is 280-320 r / min.

[0025] The technical scheme has the following beneficial effects:

[0026] The high cold-resistant waterproof plate for tunnel provided by the present application is obtained by co-extrusion of the upper layer of metallocene-polyolefin mixture, the middle layer of polyester staple fiber reinforced polyolefin, and the lower layer of modified polyolefin, and the preparation method is simple. The mechanical properties are still met at low temperature (-20℃) without cracks. Compared with the existing waterproof plate, the present application can still maintain good mechanical properties and flexibility (certain bending performance) at low temperature, and is suitable for low-temperature environment.

[0027] The high cold-resistant waterproof plate for tunnel provided by the present application uses polyester staple fiber reinforced polyolefin as the framework, which can greatly improve the tensile strength and puncture resistance. In addition, the application of silane coupling agent in polyester fiber mainly improves the interfacial bonding force between polyester fiber and matrix resin through chemical modification and interfacial reinforcement, thereby improving the overall performance of the composite material, improving the dispersion uniformity of the fiber in the matrix, and improving the processing performance and finished product quality of the material.

[0028] At the same time, the chemical bond and good interface bonding between the fibers and the matrix after the silane coupling agent treatment can buffer the stress generated by low-temperature shrinkage, so that the waterproof plate can still maintain good flexibility and is not prone to cracking even in cold environments. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be described clearly and completely below in combination with specific embodiments.

[0030] The experimental methods in the following examples are all conventional methods unless otherwise specified. The raw materials, reagent materials and the like used in the following examples are all commercially available products unless otherwise specified, and are as follows:

[0031] The polyolefin elastomer in the upper layer metallocene-polyolefin mixture of the examples and comparative examples is Exxon Mobil POE3020FL; the metallocene polyethylene is Exxon Mobil 3812CB; and the high-density polyethylene is Dushanzi Petrochemical HDPE HD5502GA.

[0032] In the middle layer polyester short fiber reinforced polyolefin, the linear low-density polyethylene is Saudi sabic LLDPE 218W; the thermoplastic polyolefin is LyondellBasell X 500F; the polyethylene wax is Honeywell AC-6; the white carbon black is Degussa fumed silica Aerosil 200 with an original particle size <300nn; and the cold-resistant toughening agent is American Dow AMPLIFY™ TY 1053H.

[0033] The lower layer modified polyolefin: the ethylene-vinyl acetate copolymer is Yangzi BASF EVA V5210J; the linear low-density polyethylene is Saudi sabic LLDPE 218W; and the high-density polyethylene is Dushanzi Petrochemical HDPE HD5502GA.

[0034] Preparation Example 1

[0035] The present preparation example provides a preparation method of modified polyester short fibers, comprising the following steps:

[0036] (1) Pretreatment of polyester short fibers: the polyester short fibers are placed in a deionized water solution containing 0.5% by mass sodium dodecyl benzene sulfonate, stirred at 50°C for 60 min, and then dried; the drying temperature is 80°C, and the drying time is 4h; wherein the ratio of the polyester short fibers to the deionized water solution is 1kg:10L;

[0037] (2) Preparation of hydrolysis solution containing active silanol groups: γ-aminopropyl triethoxysilane is added to ethanol to prepare a mixed solution with a mass fraction of 0.5%; deionized water corresponding to 5% of the mass of the γ-aminopropyl triethoxysilane is added to the mixed solution, and after the pH value is adjusted to 4-5 using acetic acid, the solution is stirred at room temperature for 0.8 h to obtain the hydrolysis solution;

[0038] (3) Preparation of modified polyester staple fiber: the pretreated polyester staple fiber is added to the hydrolysis solution, so that the pretreated staple fiber is completely immersed in the hydrolysis solution, and after stirring at room temperature at a stirring speed of 100 r / min for 120 min, the modified polyester staple fiber is obtained after filtration, washing, and drying; the washing solvent is ethanol, the drying temperature is 100°C, and the drying time is 6 h.

[0039] Preparation Example 2

[0040] The preparation example provides a preparation method of modified polyester staple fiber, which comprises the following steps:

[0041] (1) Pretreatment of polyester staple fiber: the polyester staple fiber is placed in a deionized water solution containing 1% by mass of sodium dodecyl benzene sulfonate, stirred at 55°C for 45 min, and then dried; the drying temperature is 90°C, and the drying time is 3 h; wherein the ratio of the polyester staple fiber to the deionized water solution is 1 kg:12 L;

[0042] (2) Preparation of hydrolysis solution containing active silanol groups: γ-aminopropyl triethoxysilane is added to ethanol to prepare a mixed solution with a mass fraction of 3%; deionized water corresponding to 10% of the mass of the γ-aminopropyl triethoxysilane is added to the mixed solution, and after the pH value is adjusted to 4-5, the solution is stirred at room temperature for 1 h to obtain the hydrolysis solution;

[0043] (3) Preparation of modified polyester staple fiber: the pretreated polyester staple fiber is added to the hydrolysis solution, so that the pretreated staple fiber is completely immersed in the hydrolysis solution, and after stirring at room temperature at a stirring speed of 200 r / min for 60 min, the modified polyester staple fiber is obtained after filtration, washing, and drying; the washing solvent is ethanol, the drying temperature is 100°C, and the drying time is 6 h.

[0044] Preparation Example 3

[0045] The preparation example provides a preparation method of modified polyester staple fiber, which comprises the following steps:

[0046] (1) polyester staple fiber pretreatment: the polyester staple fiber is placed in a deionized water solution containing 2% by mass of sodium dodecyl benzene sulfonate, stirred at 60°C for 30 min, and then dried; the drying temperature is 100°C, and the drying time is 2h; wherein the ratio of polyester staple fiber to deionized water solution is 1kg: 15L;

[0047] (2) preparation of a hydrolysis solution containing active silanol groups: γ-aminopropyl triethoxysilane is added to ethanol to prepare a mixed solution with a mass fraction of 5%; 20% of the mass of the γ-aminopropyl triethoxysilane is added to the mixed solution in the form of deionized water, and the pH value is adjusted to 4-5 using acetic acid before stirring at room temperature for 1.2h to obtain the hydrolysis solution;

[0048] (3) preparation of modified polyester staple fiber: the pretreated polyester staple fiber is added to the hydrolysis solution so that the pretreated staple fiber is completely immersed in the hydrolysis solution, and after stirring at room temperature at a stirring speed of 300r / min for 30 min, the modified polyester staple fiber is obtained after filtration, washing, and drying; wherein the washing solvent is ethanol, the drying temperature is 100°C, and the drying time is 6h.

[0049] Example 1

[0050] The embodiment provides a high-cold-resistance waterproof board for tunnels, and a preparation method thereof.

[0051] Step S1, preparation of an upper layer metallocene-polyolefin mixture

[0052] Step S101, in parts by weight, polyolefin elastomer POE 2 parts, metallocene polyethylene 20 parts, high-density polyethylene 20 parts, antioxidant 1010 1 part, and ultraviolet inhibitor UV-327 1 part are weighed;

[0053] Step S102, after uniformly mixing all the upper layer raw materials of step S101, the mixed upper layer raw materials are poured into a main feeding hopper, extruded, drawn, and pelletized by a double-screw granulator to prepare an upper layer metallocene-polyolefin mixture; wherein the screw temperature is 190°C, the die temperature is 200°C, and the screw rotation speed is 280r / min.

[0054] Step S2, preparation of a middle layer polyester staple fiber reinforced polyolefin

[0055] Step S201, linear low-density polyethylene 25 parts, thermoplastic polyolefin 5 parts, polyethylene wax 1 part, white carbon black 3 parts, cold-resistant toughening agent 2 parts, antioxidant 1010 1 part, and ultraviolet inhibitor UV-531 1 part are uniformly mixed;

[0056] Step S202, pour the mixed middle layer mixture in step S201 into the main feeding hopper, pour 3 parts of the modified polyester staple fiber obtained in Preparation Example 1 into the side feeding hopper, and then extrude, draw and cut through the double screw granulator to obtain the middle layer polyester staple fiber reinforced polyolefin; wherein the screw temperature is 190 DEG C, the die temperature is 200 DEG C, and the screw speed is 280 r / min.

[0057] Step S3, preparing the lower layer modified polyolefin

[0058] Step S301, weigh ethylene-vinyl acetate copolymer 10 parts, linear low density polyethylene 20 parts, high density polyethylene 20 parts, antioxidant 1010 1 part, and ultraviolet inhibitor UV-326 1 part by weight fraction;

[0059] Step S302, pour the mixed lower layer raw material in step S301 into the main feeding hopper, and then extrude, draw and cut through the double screw granulator to obtain the lower layer modified polyolefin; wherein the screw temperature is 190 DEG C, the die temperature is 200 DEG C, and the screw speed is 280 r / min.

[0060] Step S4, according to the mass ratio of 13:60:27 of the upper layer metallocene-polyolefin mixture, the middle layer polyester staple fiber reinforced polyolefin and the lower layer modified polyolefin, respectively add to the corresponding hopper, and then extrude through the three-layer co-extrusion equipment, and then cool the calender roll to obtain;

[0061] The screw temperature of the co-extrusion equipment is 200 DEG C, the die temperature is 210 DEG C, the screw speed is 280 r / min, and the coating machine roll temperature is 10 DEG C.

[0062] Example 2

[0063] The preparation method of the high cold-resistant waterproof board for tunnel provided in the embodiment comprises:

[0064] Step S1, preparing the upper layer metallocene-polyolefin mixture

[0065] Step S101, weigh polyolefin elastomer POE 3 parts, metallocene polyethylene 25 parts, high density polyethylene 25 parts, antioxidant 1010 2 parts and ultraviolet inhibitor UV-327 2 parts by weight fraction;

[0066] Step S102, after mixing all the upper layer raw materials in step S101, pour the mixed upper layer raw materials into the main feeding hopper, and then extrude, draw and cut through the double screw granulator to obtain the upper layer metallocene-polyolefin mixture; wherein the screw temperature is 200 DEG C, the die temperature is 210 DEG C, and the screw speed is 300 r / min.

[0067] Step S2, preparing the middle layer polyester staple fiber reinforced polyolefin

[0068] Step S201, uniformly mix 30 parts of linear low-density polyethylene, 7 parts of thermoplastic polyolefin, 4 parts of polyethylene wax, 5 parts of white carbon black, 3 parts of cold-resistant toughening agent, 2 parts of antioxidant 1010, and 2 parts of ultraviolet inhibitor UV-326;

[0069] Step S202, pour the mixed material in step S201 into the main feeding hopper, pour 4 parts of modified polyester short fibers obtained from Preparation Example 2 into the side feeding hopper, and then extrude, draw, and cut through the double-screw granulator to obtain the middle-layer polyester short fiber reinforced polyolefin; wherein the screw temperature is 200℃, the die temperature is 210℃, and the screw rotation speed is 300r / min.

[0070] Step S3, preparation of the lower-layer modified polyolefin

[0071] Step S301, take ethylene-vinyl acetate copolymer 12 parts, linear low-density polyethylene 28 parts, high-density polyethylene 27 parts, antioxidant 1010 2 parts, and ultraviolet inhibitor UV-326 2 parts by weight;

[0072] Step S302, pour the mixed material in step S301 into the main feeding hopper, and then extrude, draw, and cut through the double-screw granulator to obtain the lower-layer modified polyolefin; wherein the screw temperature is 200℃, the die temperature is 210℃, and the screw rotation speed is 300r / min.

[0073] Step S4, add the upper-layer metallocene-polyolefin mixture, the middle-layer polyester short fiber reinforced polyolefin, and the lower-layer modified polyolefin into the corresponding hoppers according to the mass ratio of 15:60:25, and then extrude through the three-layer co-extrusion equipment, and then cool and calender to obtain the waterproof plate.

[0074] The screw temperature of the co-extrusion equipment is 210℃, the die temperature is 220℃, the screw rotation speed is 300r / min, and the coating machine roller temperature is 20℃.

[0075] Example 3

[0076] The present embodiment provides a high-cold-resistant waterproof plate for tunnels, and the preparation method thereof comprises the following steps:

[0077] Step S1, preparation of the upper-layer metallocene-polyolefin mixture

[0078] Step S101, take polyolefin elastomer POE 4 parts, metallocene polyethylene 30 parts, high-density polyethylene 30 parts, antioxidant 2246 3 parts, and ultraviolet inhibitor UV-531 3 parts by weight;

[0079] Step S102, after mixing all the upper layer raw materials of step S101, pour the mixed upper layer raw materials into the main feeding hopper, extrude, draw and cut through the double screw granulator to prepare the upper layer metallocene-polyolefin mixture; wherein the screw temperature is 210℃, the die temperature is 220℃, and the screw speed is 320r / min.

[0080] Step S2, preparing middle layer polyester short fiber reinforced polyolefin

[0081] Step S201, mix linear low density polyethylene 35 parts, thermoplastic polyolefin 10 parts, polyethylene wax 3 parts, white carbon black 6 parts, cold resistance toughening agent 4 parts, antioxidant 2246 3 parts, and ultraviolet inhibitor UV-531 3 parts uniformly;

[0082] Step S202, pour the mixed middle layer material of step S201 into the main feeding hopper, pour the modified polyester short fiber 5 parts obtained from preparation example 3 into the side feeding hopper, extrude, draw and cut through the double screw granulator to prepare the middle layer polyester short fiber reinforced polyolefin; wherein the screw temperature is 210℃, the die temperature is 220℃, and the screw speed is 320r / min.

[0083] Step S3, preparing lower layer modified polyolefin

[0084] Step S301, in parts by weight, ethylene-vinyl acetate copolymer 15 parts, linear low density polyethylene 35 parts, high density polyethylene 35 parts, antioxidant 2246 3 parts, and ultraviolet inhibitor UV-326 3 parts are weighed;

[0085] Step S302, pour the mixed lower layer raw material of step S301 into the main feeding hopper, extrude, draw and cut through the double screw granulator to prepare the lower layer modified polyolefin; wherein the screw temperature is 210℃, the die temperature is 220℃, and the screw speed is 320r / min.

[0086] Step S4, according to the mass ratio of 17:60:23 of the upper layer metallocene-polyolefin mixture, the middle layer polyester short fiber reinforced polyolefin and the lower layer modified polyolefin, respectively add them into the corresponding hopper, extrude through the three-layer co-extrusion equipment, and then cool and calender to obtain the product.

[0087] The screw temperature of the co-extrusion equipment is 220℃, the die temperature is 230℃, the screw speed is 320r / min, and the coating machine roller temperature is 30℃.

[0088] Comparative example 1

[0089] This comparative example provides a high cold resistance waterproof board for tunnel, and the preparation method thereof comprises:

[0090] Step S1, preparing upper layer polyolefin mixture

[0091] Step S101, 3 parts of polyolefin elastomer POE, 25 parts of high-density polyethylene, 2 parts of antioxidant 1010 and 2 parts of ultraviolet resistance agent UV-327 were weighed by weight fraction;

[0092] Step S102, after the upper layer raw materials of step S101 were mixed uniformly, the mixed upper layer raw materials were poured into the main feeding hopper, and after extrusion, drawing and granulation by a double screw granulator, the upper layer metallocene-polyolefin mixture was prepared; wherein the screw temperature was 200℃, the die temperature was 210℃, and the screw speed was 300r / min.

[0093] Step S2, preparation of middle layer polyester short fiber reinforced polyolefin

[0094] Step S201, 30 parts of linear low-density polyethylene, 7 parts of thermoplastic polyolefin, 4 parts of polyethylene wax, 5 parts of white carbon black, 3 parts of cold-resistant toughening agent, 2 parts of antioxidant 1010 and 2 parts of ultraviolet resistance agent UV-326 were mixed uniformly;

[0095] Step S202, the mixed middle layer material of step S201 was poured into the main feeding hopper, 4 parts of modified polyester short fiber obtained from preparation example 2 was poured into the side feeding hopper, and after extrusion, drawing and granulation by a double screw granulator, the middle layer polyester short fiber reinforced polyolefin was prepared; wherein the screw temperature was 200℃, the die temperature was 210℃, and the screw speed was 300r / min.

[0096] Step S3, preparation of lower layer modified polyolefin

[0097] Step S301, 12 parts of ethylene-vinyl acetate copolymer, 28 parts of linear low-density polyethylene, 27 parts of high-density polyethylene, 2 parts of antioxidant 1010 and 2 parts of ultraviolet resistance agent UV-326 were weighed by weight fraction;

[0098] Step S302, the mixed lower layer raw material of step S301 was poured into the main feeding hopper, and after extrusion, drawing and granulation by a double screw granulator, the lower layer modified polyolefin was prepared; wherein the screw temperature was 200℃, the die temperature was 210℃, and the screw speed was 300r / min.

[0099] Step S4, the upper layer polyolefin mixture, the middle layer polyester short fiber reinforced polyolefin and the lower layer modified polyolefin were respectively added into the corresponding hopper according to the mass ratio of 15:60:25, and then extruded by a three-layer co-extrusion equipment, and then cooled and calendered by a roller to obtain the product.

[0100] The screw temperature of the co-extrusion equipment was 210℃, the die temperature was 200℃, the screw speed was 300r / min, and the coating machine roller temperature was 20℃.

[0101] Comparative Example 2

[0102] The present comparative example provides a high cold-resistant waterproof board for tunnel, and a preparation method thereof comprises the following steps:

[0103] Step S1, preparing upper layer metallocene-polyolefin mixture

[0104] Step S101, in weight fraction, polyolefin elastomer POE 3 parts, metallocene polyethylene 25 parts, high density polyethylene 25 parts, antioxidant 1010 2 parts and ultraviolet inhibitor UV-327 2 parts are weighed;

[0105] Step S102, after the upper layer raw materials in step S101 are uniformly mixed, the mixed upper layer raw materials are poured into the main feeding hopper, and then extruded, drawn and cut by a double screw granulator to prepare the upper layer metallocene-polyolefin mixture; wherein the screw temperature is 200 DEG C, the die temperature is 210 DEG C, and the screw speed is 300 r / min.

[0106] Step S2, preparing reinforced polyolefin

[0107] Step S201, linear low density polyethylene 30 parts, thermoplastic polyolefin 7 parts, polyethylene wax 4 parts, white carbon black 5 parts, cold-resistant toughening agent 3 parts, antioxidant 1010 2 parts and ultraviolet inhibitor UV-326 2 parts are uniformly mixed;

[0108] Step S202, the mixed middle layer material in step S201 is poured into the main feeding hopper, and then extruded, drawn and cut by a double screw granulator to prepare the reinforced polyolefin; wherein the screw temperature is 200 DEG C, the die temperature is 210 DEG C, and the screw speed is 300 r / min.

[0109] Step S3, preparing lower layer modified polyolefin

[0110] Step S301, in weight fraction, ethylene-vinyl acetate copolymer 12 parts, linear low density polyethylene 28 parts, high density polyethylene 27 parts, antioxidant 1010 2 parts and ultraviolet inhibitor UV-326 2 parts are weighed;

[0111] Step S302, the mixed lower layer raw material in step S301 is poured into the main feeding hopper, and then extruded, drawn and cut by a double screw granulator to prepare the lower layer modified polyolefin; wherein the screw temperature is 200 DEG C, the die temperature is 210 DEG C, and the screw speed is 300 r / min.

[0112] Step S4, the upper layer metallocene-polyolefin mixture, the middle layer polyolefin and the lower layer modified polyolefin are respectively added into the corresponding hopper according to the mass ratio of 15:60:25, and then extruded by a three-layer co-extrusion equipment, and then cooled and calendered by a roller to obtain the high cold-resistant waterproof board for tunnel.

[0113] The screw temperature of the co-extrusion equipment is 210 DEG C, the die temperature is 200 DEG C, the screw rotation speed is 300 r / min, and the coating machine roller temperature is 20 DEG C.

[0114] Comparative Example 3

[0115] The present comparative example provides a high cold-resistant waterproof board for tunnels, and a preparation method thereof comprises the following steps:

[0116] Step S1, preparing an upper layer metallocene-polyolefin mixture

[0117] Step S101, in weight parts, polyolefin elastomer POE 3 parts, metallocene polyethylene 25 parts, high-density polyethylene 25 parts, antioxidant 1010 2 parts, and ultraviolet inhibitor UV-327 2 parts are weighed;

[0118] Step S102, after uniformly mixing all the upper layer raw materials of step S101, the mixed upper layer raw materials are poured into the main feeding hopper, and after extrusion, drawing, and granulation by a double-screw granulator, an upper layer metallocene-polyolefin mixture is prepared; wherein the screw temperature is 200 DEG C, the die temperature is 210 DEG C, and the screw rotation speed is 300 r / min.

[0119] Step S2, preparing a middle layer polyester short fiber reinforced polyolefin

[0120] Step S201, linear low-density polyethylene 30 parts, thermoplastic polyolefin 7 parts, polyethylene wax 4 parts, white carbon black 5 parts, cold-resistant toughening agent 3 parts, antioxidant 1010 2 parts, and ultraviolet inhibitor UV-326 2 parts are uniformly mixed;

[0121] Step S202, the mixed middle layer material of step S201 is poured into the main feeding hopper, and the modified polyester short fiber obtained in Preparation Example 2 is poured into the side feeding hopper, and after extrusion, drawing, and granulation by a double-screw granulator, a middle layer polyester short fiber reinforced polyolefin is prepared; wherein the screw temperature is 200 DEG C, the die temperature is 210 DEG C, and the screw rotation speed is 300 r / min.

[0122] Step S3, the upper layer metallocene-polyolefin mixture and the middle layer polyester short fiber reinforced polyolefin are respectively added to the corresponding hopper according to a mass ratio of 15:60, and are extruded by a co-extrusion equipment, and then are cooled and calendered by a roller to obtain a product.

[0123] The screw temperature of the co-extrusion equipment is 210 DEG C, the die temperature is 200 DEG C, the screw rotation speed is 300 r / min, and the coating machine roller temperature is 20 DEG C.

[0124] Comparative Example 4

[0125] The present comparative example provides a high cold-resistant waterproof board for tunnels, and a preparation method thereof comprises the following steps:

[0126] Step S1, in parts by weight, polyolefin elastomer POE 3 parts, metallocene polyethylene 25 parts, high density polyethylene 25 parts, antioxidant 1010 2 parts and anti-ultraviolet agent UV-327 2 parts were mixed uniformly to obtain a mixture A;

[0127] Step S2, linear low density polyethylene 30 parts, thermoplastic polyolefin 7 parts, polyethylene wax 4 parts, white carbon black 5 parts, cold-resistant toughening agent 3 parts, antioxidant 1010 2 parts, anti-ultraviolet agent UV-326 2 parts were mixed uniformly to obtain a mixture B, and modified polyester short fiber 4 parts were weighed for standby;

[0128] Step S3, in parts by weight, ethylene-vinyl acetate copolymer 12 parts, linear low density polyethylene 28 parts, high density polyethylene 27 parts, antioxidant 1010 2 parts, anti-ultraviolet agent UV-326 2 parts were mixed uniformly to obtain a mixture C;

[0129] Step S4, according to the mass ratio of 15:60:25 of mixture A, mixture B and mixture C, a double screw extruder was added to perform extrusion molding, and then a cooling calender roller was obtained.

[0130] The screw temperature of the double screw extruder was 210 DEG C, the die temperature was 200 DEG C, the screw speed was 300 r / min, and the coating machine roller temperature was 20 DEG C.

[0131] Effect example:

[0132] The products prepared in Examples 1-3 and Comparative Examples 1-4 were tested for tear strength, tensile strength at break, elongation at break, and puncture strength, and the results are shown in Table 1.

[0133] The performance test indicators and methods are as follows: tear strength, tensile strength at break, elongation at break, and puncture strength are tested according to the standard QCR562.1-2018.

[0134] Table 1 Performance test results of products prepared in each example and comparative example

[0135]

[0136] As shown in Table 1, the high cold-resistant waterproof board for tunnel provided by the application still maintains excellent mechanical properties at low temperature.

[0137] Effect example 2

[0138] The products prepared in Examples 1-3 and Comparative Examples 1-4 were tested for low temperature flexibility according to the standard GB-T 328.14-2007, and the results are shown in Table 2.

[0139] Table 2 Low temperature flexibility test results of products prepared in each example and comparative example

[0140]

[0141] Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can be modified by those skilled in the art, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-cold-resistant and waterproof liner for tunnels, characterized in that, The waterproof membrane is prepared from an upper layer of metallocene-polyolefin mixture, a middle layer of polyester short fiber reinforced polyolefin, and a lower layer of modified polyolefin in a mass ratio of (13~17):60:(23~27). By weight, the raw materials of the upper metallocene-polyolefin mixture include: 2-4 parts of polyolefin elastomer POE, 20-30 parts of metallocene polyethylene, 20-30 parts of high-density polyethylene, 1-3 parts of antioxidant and 1-3 parts of UV stabilizer; By weight, the raw materials for the lower layer modified polyolefin include: 10-15 parts of ethylene-vinyl acetate copolymer, 20-35 parts of linear low-density polyethylene, 20-35 parts of high-density polyethylene, 1-3 parts of antioxidant, and 1-3 parts of UV stabilizer. By weight, the raw materials of the middle layer polyester short fiber reinforced polyolefin include: 25-35 parts of linear low-density polyethylene, 5-10 parts of thermoplastic polyolefin, 3-5 parts of modified polyester short fiber, 1-3 parts of polyethylene wax, 3-6 parts of fumed silica, 2-4 parts of cold-resistant toughening agent, 1-3 parts of antioxidant, and 1-3 parts of UV stabilizer. The modified polyester staple fiber has a length of 3-6 mm and is a polyester staple fiber treated with a silane coupling agent. The cold-resistant toughening agent is a maleic anhydride graft copolymer. The method for preparing the modified polyester staple fiber includes: (1) Pretreatment of polyester staple fiber: The polyester staple fiber is placed in a deionized water solution containing sodium dodecylbenzenesulfonate with a mass fraction of 0.5%~2%, stirred at 50~60℃ for 30~60min and then dried; wherein, the drying temperature is 80~100℃ and the drying time is 2~4h; the ratio of polyester staple fiber to deionized water solution is 1kg:(10~15)L; (2) Preparation of hydrolysis solution containing active silanol groups: Add γ-aminopropyltriethoxysilane to ethanol to prepare a mixed solution with a mass fraction of 0.5% to 5%; add deionized water equivalent to 5% to 20% of the mass of γ-aminopropyltriethoxysilane to the mixed solution, adjust the pH value to 4 to 5 with acetic acid, and stir at room temperature for 0.8 to 1.2 h to obtain the hydrolysis solution; (3) Preparation of modified polyester short fibers: The pretreated polyester short fibers are added to the hydrolysis solution and stirred at a stirring speed of 100~300r / min for 30~120min at room temperature. After filtration, washing and drying, the modified polyester short fibers are obtained.

2. The high cold-resistant and waterproof liner for tunnels according to claim 1, characterized in that, The antioxidant is selected from at least one of phenolic antioxidants and amine antioxidants; the UV protectant is selected from at least one of UV-327, UV-531, and UV-326.

3. The high cold-resistant waterproof membrane for tunnels according to claim 1, characterized in that, The preparation method of the middle layer polyester short fiber reinforced polyolefin includes: Step S201: Mix linear low-density polyethylene, thermoplastic polyolefin, polyethylene wax, silica, cold-resistant toughening agent, antioxidant and UV stabilizer evenly to obtain the middle layer mixture; Step S202: Pour the mixed intermediate layer material from step S201 into the main feed hopper, and pour the modified polyester short fibers into the side feed hopper. After extrusion, stretching, and pelletizing by a twin-screw granulator, the intermediate layer polyester short fiber reinforced polyolefin is produced.

4. The high cold-resistant waterproof membrane for tunnels according to claim 1, characterized in that, The thickness of the high cold-resistant waterproof liner used in the tunnel is 1.5~2mm.

5. A method for preparing a high cold-resistant and waterproof tunnel lining as described in any one of claims 1 to 4, characterized in that, The method includes: The upper metallocene-polyolefin mixture, the middle polyester short fiber reinforced polyolefin and the lower modified polyolefin are added to the corresponding hoppers respectively, and extruded through a three-layer co-extrusion device, and then cooled and calendered through rollers to obtain the final product. The screw temperature of the co-extrusion equipment is 200~220℃, the die temperature is 210~230℃, the screw speed is 280~320r / min, and the coating machine roller temperature is 10~30℃.

6. The method for preparing a high cold-resistant and waterproof tunnel lining according to claim 5, characterized in that, Both the upper metallocene-polyolefin mixture and the lower modified polyolefin are obtained by extruding, drawing, and pelletizing all raw materials after they are mixed evenly using a twin-screw granulator. The twin-screw granulator has a screw temperature of 190~210℃, a die temperature of 200~220℃, and a screw speed of 280~320r / min.

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