Polyethylene composite hose and preparation method thereof

Abstract

The invention belongs to the technical field of polyethylene hoses, and provides a polyethylene composite hose and a preparation method thereof.The polyethylene composite hose sequentially comprises an inner layer, a secondary inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer and an outer layer from inside to outside; the secondary inner layer is prepared from the following components in parts by weight: 100 parts of polylactic acid, 5 to 8 parts of modified talcum powder, 0.5 to 2 parts of antioxidant and 0.1 to 0.5 part of lubricant. The preparation method comprises the following steps: step 1, respectively adding raw materials of each layer into different mixers according to a ratio, and mixing to respectively obtain a mixture of the raw materials of each layer; and 2, respectively introducing the mixture of each layer of raw materials obtained in the step 1 into a multi-layer co-extrusion extruder, and carrying out extrusion molding, cooling curing and cutting correction to obtain the polyethylene composite hose. The polyethylene composite hose provided by the invention is smooth in surface and attractive in appearance, and has the advantages of high mechanical strength, good oxygen and water resistance, wear resistance, stable structure and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyethylene hoses, and particularly relates to a polyethylene composite hose and a preparation method thereof. Background Art

[0002] Plastic pipes have the advantages of light weight, high strength, simple manufacturing method, low economic cost, convenient processing and use, corrosion resistance, long service life, etc. They have gradually replaced pipes such as metal and cement and become the main application pipes in fields such as urban construction, rural water network laying, and electrical transmission. Plastic hoses generally use polyester (PET), polyethylene (PE), polypropylene (PP), etc. as raw materials. After adding corresponding organic solvents and being heated at high temperature, they are formed by blow molding, extrusion blowing or injection molding through plastic molds. Hose packaging is convenient to carry, not easily broken, low in cost, and convenient to produce. At the same time, it has acid and alkali resistance characteristics and also meets the requirements of food packaging. It is also conducive to recycling after use. Therefore, the application fields of hose packaging are extensive, including but not limited to the cosmetics industry, food industry, pharmaceutical industry, chemical industry, etc.

[0003] At present, most plastic hoses use polyethylene as raw materials. Polyethylene hoses have very good flexibility and extremely high elongation at break, and have excellent construction adaptability, bringing great convenience to pipeline construction. However, ordinary polyethylene hoses still have great shortcomings in wear resistance and mechanical properties. At the same time, the application scenarios of plastic hoses are diverse, and hoses are required to have properties such as sealing and anti-oxidation. Moreover, with the increasing requirements for quality in the industry, the appearance and comfort of hoses are also gradually improved. Therefore, they often cannot meet the long-term use requirements in some application scenarios, which also brings certain restrictions to the further development of polyethylene hoses. Therefore, the surface state of polyethylene plastic hoses is rough and needs to be additionally printed, and the sealing and compressive properties do not meet the standards, which are still problems to be solved urgently. Summary of the Invention

[0004] The purpose of the present invention is to provide a polyethylene composite hose and a preparation method thereof to solve the problem of poor mechanical properties of polyethylene hoses in the prior art.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] In the first aspect of the present invention, a polyethylene composite hose is provided, which sequentially includes an inner layer, a sub-inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer, and an outer layer from inside to outside; the material of the sub-inner layer includes the following components in parts by weight: 100 parts of polylactic acid, 5 - 8 parts of modified talcum powder, 0.5 - 2 parts of antioxidant, and 0.1 - 0.5 parts of lubricant.

[0007] As a preferred scheme of the present invention, the modified talcum powder is prepared by the following steps:

[0008] Glacial acetic acid is added to the mixed solution of absolute ethanol and deionized water, and the pH value is adjusted to 4.5 - 5.0. 3-mercaptopropyltriethoxysilane and trihexyl(tetradecyl)phosphonium decanoate are added, and the temperature is raised to 40 - 45 °C for hydrolysis for 12 - 15 min. Talcum powder is added, and ultrasonic dispersion is carried out for 15 - 20 min. Then the temperature is raised to 80 - 85 °C and stirring reaction is carried out for 22 - 24 h. After washing and freeze-drying, modified talcum powder is obtained. Using 3-mercaptopropyltriethoxysilane to modify the surface of hydrotalcite improves the dispersibility of hydrotalcite in the polylactic acid matrix and the compatibility between molecules. When hydrotalcite and polylactic acid are melt-blended, the toughness of polylactic acid can be significantly improved.

[0009] As a preferred embodiment of the present invention, the dosage ratio of glacial acetic acid, absolute ethanol, deionized water, 3-mercaptopropyltriethoxysilane, trihexyl(tetradecyl)phosphonium decanoate and talcum powder is 3.5 - 4.0 mL : 95 mL : 45 mL : 2.0 - 2.2 g : 2.0 - 2.2 g : 0.20 - 0.23 g.

[0010] As a preferred embodiment of the present invention, the particle size of the talcum powder is 60 - 100 nm. The smaller the particle size of the hydrotalcite, the larger the specific surface area of the talcum powder, which promotes better nucleation effect of polylactic acid, and further increases the mechanical properties of the polylactic acid material.

[0011] As a preferred embodiment of the present invention, the antioxidant is one of antioxidant 1010, antioxidant 1076, antioxidant 168 and antioxidant 626; the lubricant is one of magnesium stearate, calcium stearate and ethylene bisstearamide.

[0012] As a preferred embodiment of the present invention, the materials of the inner layer and the outer layer include the following components in parts by weight: 20 - 50 parts of low-density polyethylene, 20 - 50 parts of high-density polyethylene, 5 - 23 parts of linear low-density polyethylene, and 5 - 12 parts of metallocene polyethylene.

[0013] As a preferred embodiment of the present invention, the materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene. Maleic anhydride grafted polyethylene significantly improves its adhesion ability to non-polar materials (such as EVOH) by introducing polar groups into the polyethylene molecular chain. These polar groups can form chemical bonds with non-polar materials, thereby enhancing the adhesion strength.

[0014] As a preferred embodiment of the present invention, the material of the intermediate layer is ethylene-vinyl alcohol copolymer (EVOH). EVOH combines the processability of polyethylene and the barrier properties of polyvinyl alcohol, having extremely high gas barrier properties and good mechanical strength, stretchability, abrasion resistance and cold resistance, enabling EVOH to be well combined with other materials in the application of the intermediate layer of polyethylene hoses, improving the overall processing efficiency and product quality of the hoses, and extending the service life of the hoses.

[0015] As a preferred embodiment of the present invention, the thickness ratio of the inner layer, the sub-inner layer, the inner adhesive layer, the intermediate layer, the outer adhesive layer and the outer layer is 25-35:15-25:2.5-4.0:2.5-4.0:2.5-4.0:25-35.

[0016] The second aspect of the present invention provides a method for preparing a polyethylene composite hose, comprising the following steps:

[0017] Step 1: Add the raw materials of each layer into different mixers according to the ratio for mixing respectively to obtain the mixed materials of the raw materials of each layer;

[0018] Step 2: Feed the mixed materials of the raw materials of each layer obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder respectively, extrude and form, cool and solidify, cut and correct to obtain a polyethylene composite hose.

[0019] The beneficial effects of the present invention:

[0020] 1) The present invention adopts a six-layer co-extrusion structure, and the outer layer and the inner layer use the same material, both using low-density polyethylene, high-density polyethylene, linear low-density polyethylene and metallocene polyethylene as the inner and outer layer materials. By reasonably proportioning different types of polyethylene, the inner and outer layers of the hose have high abrasion resistance and impact resistance, can withstand external friction and impact, and thus extend the service life of the hose; at the same time, it can reduce production costs and save economy while maintaining material properties. The outer adhesive layer and the inner adhesive layer both use maleic anhydride grafted polyethylene as the adhesive. Maleic anhydride grafted polyethylene has excellent bonding properties, and has high bonding strength and long-lasting and stable bonding with the intermediate layer, the outer layer and the sub-inner layer. The intermediate layer uses EVOH as the raw material, effectively improving the oxygen barrier property and water resistance of the composite hose.

[0021] 2) Based on the five - layer composite pipe, the present invention adds a layer of material, namely the sub - inner layer, to form a six - layer composite hose. This layer adds the biodegradable material polylactic acid as the base material, and then is co - extruded after being uniformly mixed with modified hydrotalcite, antioxidant and lubricant to form the sub - inner layer. The addition of modified hydrotalcite can improve the crystallization performance of polylactic acid, improve the mechanical properties of polylactic acid, making polylactic acid have high strength and high toughness. As the sub - inner layer, it can provide sufficient mechanical strength and durability, and extend the service life of the polyethylene composite hose.

[0022] 3) The present invention forms a composite hose with a six - layer structure by separately mixing the raw materials of each layer and then extruding them layer by layer through a six - layer co - extrusion extruder. Using the six - layer co - extrusion process, the composite hose has better strength and stability. At the same time, independent stress distributions can be formed between each layer, improving the overall performance and service life of the composite hose.

[0023] 4) The preparation method of a polyethylene composite hose provided by the present invention has simple preparation process, easily available raw materials, high production efficiency, and is suitable for large - scale industrial production. At the same time, the prepared polyethylene composite hose has a smooth surface, beautiful appearance, and has the advantages of high mechanical strength, good oxygen - and water - barrier performance, wear resistance, and stable structure, and has a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Figure 1 It is a hierarchical schematic diagram of a polyethylene composite hose provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1

[0028] This example provides a modified talcum powder, and the preparation steps are as follows:

[0029] Add 3.5 mL of glacial acetic acid to a mixed solution of 95 mL of absolute ethanol and 45 mL of deionized water, adjust the pH value to 4.5, add 2.0 g of 3-mercaptopropyltriethoxysilane and 2.0 g of trihexyl(tetradecyl)phosphonium decanoate, raise the temperature to 40 °C and hydrolyze for 15 min, add 0.20 g of talcum powder (particle size of 60 nm), ultrasonically disperse for 15 min, raise the temperature to 80 °C and carry out a stirring reaction for 24 h, wash three times with deionized water and absolute ethanol respectively, and freeze-dry to obtain modified talcum powder.

[0030] Example 2

[0031] This example provides a modified talcum powder, and the preparation steps are as follows:

[0032] Add 3.8 mL of glacial acetic acid to a mixed solution of 95 mL of absolute ethanol and 45 mL of deionized water, adjust the pH value to 4.5, add 2.0 g of 3-mercaptopropyltriethoxysilane and 2.0 g of trihexyl(tetradecyl)phosphonium decanoate, raise the temperature to 40 °C and hydrolyze for 15 min, add 0.21 g of talcum powder (particle size of 60 nm), ultrasonically disperse for 15 min, raise the temperature to 80 °C and carry out a stirring reaction for 24 h, wash three times with deionized water and absolute ethanol respectively, and freeze-dry to obtain modified talcum powder.

[0033] Example 3

[0034] This example provides a modified talcum powder, and the preparation steps are as follows:

[0035] Add 4.0 mL of glacial acetic acid to a mixed solution of 95 mL of absolute ethanol and 45 mL of deionized water, adjust the pH value to 4.5, add 2.2 g of 3-mercaptopropyltriethoxysilane and 2.2 g of trihexyl(tetradecyl)phosphonium decanoate, raise the temperature to 40 °C and hydrolyze for 15 min, add 0.23 g of talcum powder (particle size of 60 nm), ultrasonically disperse for 15 min, raise the temperature to 80 °C and carry out a stirring reaction for 24 h, wash three times with deionized water and absolute ethanol respectively, and freeze-dry to obtain modified talcum powder.

[0036] Example 4

[0037] This example provides a polyethylene composite hose and its preparation method:

[0038] A polyethylene composite hose includes an inner layer, a sub-inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer, and an outer layer in sequence from the inside to the outside; the thickness ratio of the inner layer, sub-inner layer, inner adhesive layer, middle layer, outer adhesive layer, and outer layer is 25:15:2.5:2.5:2.5:25.

[0039] The material of the second inner layer comprises the following components in parts by weight: 100 parts of polylactic acid, 5 parts of the modified talcum powder in Example 1, 0.5 part of antioxidant 1010, and 0.1 part of magnesium stearate;

[0040] The materials of the inner layer and the outer layer comprise the following components in parts by weight: 20 parts of low-density polyethylene, 20 parts of high-density polyethylene, 5 parts of linear low-density polyethylene, and 5 parts of metallocene polyethylene;

[0041] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0042] The material of the middle layer is ethylene-vinyl alcohol copolymer.

[0043] The preparation method of the above polyethylene composite hose is as follows:

[0044] Step 1: Add the raw materials of each layer into different mixers according to the ratio for mixing respectively to obtain the mixed materials of the raw materials of each layer;

[0045] Step 2: Respectively feed the mixed materials of the raw materials of each layer obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder, and the sixth extruder for extrusion molding, cooling and solidifying, and cutting and correcting to obtain the polyethylene composite hose.

[0046] Example 5

[0047] It is different from Example 4 only in that the modified hydrotalcite in Example 1 in the raw materials of the second inner layer is replaced with the modified hydrotalcite in Example 2, and the amount in parts by weight remains unchanged:

[0048] A polyethylene composite hose comprises, from the inside to the outside in sequence, an inner layer, a second inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer, and an outer layer; wherein the thickness ratio of the inner layer, the second inner layer, the inner adhesive layer, the middle layer, the outer adhesive layer, and the outer layer is 25:15:2.5:2.5:2.5:25.

[0049] The material of the second inner layer comprises the following components in parts by weight: 100 parts of polylactic acid, 5 parts of the modified talcum powder in Example 2, 0.5 part of antioxidant 1010, and 0.1 part of magnesium stearate;

[0050] The materials of the inner layer and the outer layer comprise the following components in parts by weight: 20 parts of low-density polyethylene, 20 parts of high-density polyethylene, 5 parts of linear low-density polyethylene, and 5 parts of metallocene polyethylene;

[0051] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0052] The material of the middle layer is ethylene-vinyl alcohol copolymer.

[0053] The preparation method of the above-mentioned polyethylene composite hose is as follows:

[0054] Step 1: Add the raw materials of each layer according to the ratio into different mixers for mixing respectively to obtain the mixed materials of the raw materials of each layer;

[0055] Step 2: Respectively feed the mixed materials of the raw materials of each layer obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder, extrude and form, cool and solidify, cut and correct to obtain the polyethylene composite hose.

[0056] Example 6

[0057] It is only different from Example 4 in that the modified hydrotalcite in Example 1 in the sub-inner layer raw materials is replaced with the modified hydrotalcite in Example 2, and the dosage parts remain unchanged:

[0058] A polyethylene composite hose, which sequentially includes an inner layer, a sub-inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer and an outer layer from inside to outside; wherein the thickness ratio of the inner layer, the sub-inner layer, the inner adhesive layer, the middle layer, the outer adhesive layer and the outer layer is 25:15:2.5:2.5:2.5:25.

[0059] The material of the sub-inner layer includes the following components in parts by weight: 100 parts of polylactic acid, 5 parts of the modified talcum powder in Example 3, 0.5 part of antioxidant 1010, and 0.1 part of magnesium stearate;

[0060] The materials of the inner layer and the outer layer include the following components in parts by weight: 20 parts of low-density polyethylene, 20 parts of high-density polyethylene, 5 parts of linear low-density polyethylene, and 5 parts of metallocene polyethylene;

[0061] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0062] The material of the middle layer is ethylene-vinyl alcohol copolymer.

[0063] The preparation method of the above-mentioned polyethylene composite hose is as follows:

[0064] Step 1: Add the raw materials of each layer according to the ratio into different mixers for mixing respectively to obtain the mixed materials of the raw materials of each layer;

[0065] Step 2: Respectively feed the mixed materials of the raw materials of each layer obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder, extrude and form, cool and solidify, cut and correct to obtain the polyethylene composite hose.

[0066] Example 7

[0067] It is only different from Example 4 in that the raw materials and dosages of the sub-inner layer are different:

[0068] A polyethylene composite hose, which successively includes an inner layer, a sub-inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer and an outer layer from the inside to the outside; wherein the thickness ratio of the inner layer, the sub-inner layer, the inner adhesive layer, the middle layer, the outer adhesive layer and the outer layer is 25:15:2.5:2.5:2.5:25.

[0069] The material of the sub-inner layer includes the following components in parts by weight: 100 parts of polylactic acid, 8 parts of modified talcum powder in Example 1, 0.8 part of antioxidant 1010, and 0.15 part of magnesium stearate;

[0070] The materials of the inner layer and the outer layer include the following components in parts by weight: 20 parts of low-density polyethylene, 20 parts of high-density polyethylene, 5 parts of linear low-density polyethylene, and 5 parts of metallocene polyethylene;

[0071] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0072] The material of the middle layer is ethylene-vinyl alcohol copolymer.

[0073] The preparation method of the above polyethylene composite hose is as follows:

[0074] Step 1: Add the raw materials of each layer into different mixers according to the ratio for mixing respectively to obtain the mixed materials of the raw materials of each layer;

[0075] Step 2: Respectively feed the mixed materials of the raw materials of each layer obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder, extrude and form, cool and solidify, and cut and correct to obtain a polyethylene composite hose.

[0076] Example 8

[0077] It is only different from Example 4 in that the raw materials and dosages of the sub-inner layer are different:

[0078] A polyethylene composite hose, which successively includes an inner layer, a sub-inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer and an outer layer from the inside to the outside; wherein the thickness ratio of the inner layer, the sub-inner layer, the inner adhesive layer, the middle layer, the outer adhesive layer and the outer layer is 25:15:2.5:2.5:2.5:25.

[0079] The material of the sub-inner layer includes the following components in parts by weight: 100 parts of polylactic acid, 7 parts of modified talcum powder in Example 1, 0.5 part of antioxidant 1010, and 0.3 part of magnesium stearate;

[0080] The materials of the inner layer and the outer layer include the following components in parts by weight: 20 parts of low-density polyethylene, 20 parts of high-density polyethylene, 5 parts of linear low-density polyethylene, and 5 parts of metallocene polyethylene;

[0081] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0082] The material of the intermediate layer is ethylene-vinyl alcohol copolymer.

[0083] The preparation method of the above polyethylene composite hose is as follows:

[0084] Step 1: Add the raw materials of each layer into different mixers according to the ratio for mixing respectively to obtain the mixed materials of the raw materials of each layer;

[0085] Step 2: Feed the mixed materials of the raw materials of each layer obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder respectively, extrude and form, cool and solidify, cut and correct to obtain the polyethylene composite hose.

[0086] Example 9

[0087] It is only different from Example 4 in that the dosage of the raw materials of the inner layer and the outer layer is different:

[0088] A polyethylene composite hose, which successively includes an inner layer, a sub-inner layer, an inner adhesive layer, an intermediate layer, an outer adhesive layer and an outer layer from the inside to the outside; wherein the thickness ratio of the inner layer, the sub-inner layer, the inner adhesive layer, the intermediate layer, the outer adhesive layer and the outer layer is 25:15:2.5:2.5:2.5:25.

[0089] The material of the sub-inner layer includes the following components in parts by weight: 100 parts of polylactic acid, 5 parts of the modified talcum powder in Example 1, 0.5 part of antioxidant 1010, and 0.1 part of magnesium stearate;

[0090] The materials of the inner layer and the outer layer include the following components in parts by weight: 50 parts of low-density polyethylene, 50 parts of high-density polyethylene, 23 parts of linear low-density polyethylene, and 12 parts of metallocene polyethylene;

[0091] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0092] The material of the intermediate layer is ethylene-vinyl alcohol copolymer.

[0093] The preparation method of the above polyethylene composite hose is as follows:

[0094] Step 1: Add the raw materials of each layer into different mixers according to the ratio for mixing respectively to obtain the mixed materials of the raw materials of each layer;

[0095] Step 2: Respectively feed the mixture materials of each layer of raw materials obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder, perform extrusion molding, cooling and solidification, and cutting and correction to obtain a polyethylene composite hose.

[0096] Example 10

[0097] It is only different from Example 4 in that the dosages of the raw materials for the inner layer and the outer layer are different:

[0098] A polyethylene composite hose, which sequentially includes an inner layer, a sub-inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer and an outer layer from inside to outside; wherein the thickness ratio of the inner layer, the sub-inner layer, the inner adhesive layer, the middle layer, the outer adhesive layer and the outer layer is 25:15:2.5:2.5:2.5:25.

[0099] The material of the sub-inner layer includes the following components in parts by weight: 100 parts of polylactic acid, 5 parts of the modified talcum powder in Example 1, 0.5 part of antioxidant 1010, and 0.1 part of magnesium stearate;

[0100] The materials of the inner layer and the outer layer include the following components in parts by weight: 35 parts of low-density polyethylene, 40 parts of high-density polyethylene, 13 parts of linear low-density polyethylene, and 8 parts of metallocene polyethylene;

[0101] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0102] The material of the middle layer is ethylene-vinyl alcohol copolymer.

[0103] The preparation method of the above-mentioned polyethylene composite hose is as follows:

[0104] Step 1: Respectively add the raw materials of each layer into different mixers according to the ratio for mixing to respectively obtain the mixture materials of each layer of raw materials;

[0105] Step 2: Respectively feed the mixture materials of each layer of raw materials obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder, perform extrusion molding, cooling and solidification, and cutting and correction to obtain a polyethylene composite hose.

[0106] Example 11

[0107] It is only different from Example 4 in that the thickness ratio of each layer is different:

[0108] A polyethylene composite hose, which sequentially includes an inner layer, a sub-inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer and an outer layer from inside to outside; wherein the thickness ratio of the inner layer, the sub-inner layer, the inner adhesive layer, the middle layer, the outer adhesive layer and the outer layer is 35:20:3:3:3:35.

[0109] The material of the second inner layer comprises the following components in parts by weight: 100 parts of polylactic acid, 5 parts of the modified talcum powder in Example 1, 0.5 part of antioxidant 1010, and 0.1 part of magnesium stearate;

[0110] The materials of the inner layer and the outer layer comprise the following components in parts by weight: 20 parts of low-density polyethylene, 20 parts of high-density polyethylene, 5 parts of linear low-density polyethylene, and 5 parts of metallocene polyethylene;

[0111] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0112] The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene;

[0113] The material of the middle layer is ethylene-vinyl alcohol copolymer.

[0114] The preparation method of the above polyethylene composite hose is as follows:

[0115] Step 1: Add the raw materials of each layer into different mixers according to the ratio for mixing respectively to obtain the mixed materials of the raw materials of each layer;

[0116] Step 2: Feed the mixed materials of the raw materials of each layer obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder respectively, extrude and form, cool and solidify, cut and correct to obtain the polyethylene composite hose.

[0117] Comparative Example 1

[0118] The difference from Example 4 is only that the polyethylene composite hose does not include the second inner layer and is a five-layer structure composite hose:

[0119] A polyethylene composite hose comprises an inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer and an outer layer in sequence from the inside to the outside.

[0120] Comparative Example 2

[0121] The difference from Example 4 is only that the modified hydrotalcite is not added to the raw materials of the second inner layer:

[0122] The material of the second inner layer comprises the following components in parts by weight: 100 parts of polylactic acid, 0.5 part of antioxidant 1010, and 0.1 part of magnesium stearate.

[0123] Comparative Example 3

[0124] Replace 5 parts of the modified hydrotalcite in Example 1 in the raw materials of the second inner layer with 3.5 parts of the modified hydrotalcite in Example 1.

[0125] Comparative Example 4

[0126] Replace 5 parts of the modified hydrotalcite in Example 1 in the sub-inner layer raw materials with 9.5 parts of the modified hydrotalcite in Example 1.

[0127] Comparative Example 5

[0128] It is only different from Example 4 in that the raw materials and dosages of the sub-inner layer are different:

[0129] The materials of the sub-inner layer include the following components in parts by weight: 85 parts of polylactic acid, 5 parts of the modified talcum powder in Example 1, 0.5 part of antioxidant 1010, and 0.1 part of magnesium stearate.

[0130] Comparative Example 6

[0131] It is only different from Example 4 in that the raw material dosages of the inner layer and the outer layer are different:

[0132] The materials of the inner layer and the outer layer include the following components in parts by weight: 15 parts of low-density polyethylene, 20 parts of high-density polyethylene, 5 parts of linear low-density polyethylene, and 5 parts of metallocene polyethylene.

[0133] Comparative Example 7

[0134] It is only different from Example 4 in that the thickness ratios of each layer are different:

[0135] Among them, the thickness ratios of the inner layer, the sub-inner layer, the inner adhesive layer, the middle layer, the outer adhesive layer, and the outer layer are 15:15:2.5:2.5:2.5:25.

[0136] Perform the following performance tests on the polyethylene composite hoses obtained in Examples 4 - 11 and Comparative Examples 1 - 7:

[0137] 1) Tensile strength: According to the standard of GB / T 8804.1 - 2003, use a universal material testing machine (range of 100 kN, stroke of 900 mm, separation speed of 1 - 500 mm / min) to conduct a tensile strength performance test at 20 °C;

[0138] 2) Oxygen transmission rate: According to the standard of GB / T 29336 - 2012, test the oxygen transmission rate;

[0139] 3) Compressive performance: The conditions for the compressive test are: After sealing the tail of the soft multi-layer plastic hose, cool it in the greenhouse for 10 min, and extrude the hose under 2 bars of the soft multi-layer plastic hose to observe the hose shape;

[0140] 4) Deformation amount: The test conditions for the deformation amount are to take a 15-mm spline of the soft multi-layer plastic hose, clamp the two ends of the spline on the fixtures of the tensile machine respectively, set the tensile speed to 100 mm / min, and the tensile force to 60 N, and record the deformation amount of the spline at this time.

[0141] The above results are shown in Table 1 as follows:

[0142] Table 1

[0143]

[0144]

[0145] As can be seen from Table 1, compared with the polyethylene composite hoses prepared in Comparative Examples 1-7, the polyethylene composite hoses obtained in Examples 4-11 have a stable structure and have more excellent mechanical properties, compressive properties and barrier properties. It can be seen that the preparation method of a polyethylene composite hose provided by the present invention is simple, the raw materials are easy to obtain, the production efficiency is high, and it is suitable for large-scale industrial production; at the same time, the prepared polyethylene composite hose has the advantages of high mechanical strength, good oxygen and water barrier properties, wear resistance, stable structure, etc., and has a wide range of application scenarios.

[0146] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0147] Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments and equipment used in this application can be obtained through the market or can be prepared by existing methods.

[0148] Unless otherwise specifically stated, all embodiments and optional embodiments of this application can be combined with each other to form new technical solutions, and all technical features and optional technical features of this application can be combined with each other to form new technical solutions.

[0149] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A polyethylene composite hose, characterized in that, It successively includes an inner layer, a sub-inner layer, an inner adhesive layer, a middle layer, an outer adhesive layer and an outer layer from the inside to the outside; the material of the sub-inner layer includes the following components in parts by weight: 100 parts of polylactic acid, 5 - 8 parts of modified talc powder, 0.5 - 2 parts of antioxidant, and 0.1 - 0.5 parts of lubricant.

2. The polyethylene composite hose according to claim 1, characterized in that, The modified talc powder is prepared by the following steps: Add glacial acetic acid into the mixed solution of absolute ethanol and deionized water, adjust the pH value to 4.5 - 5.0, add 3-mercaptopropyltriethoxysilane and trihexyl(tetradecyl)phosphonium decanoate, raise the temperature to 40 - 45°C and hydrolyze for 12 - 15 min, add talc powder, ultrasonically disperse for 15 - 20 min, raise the temperature to 80 - 85°C and carry out stirring reaction for 22 - 24 h, wash, and freeze-dry to obtain the modified talc powder.

3. A polyethylene composite hose according to claim 1, characterized in that, The dosage ratio of glacial acetic acid, absolute ethanol, deionized water, 3-mercaptopropyltriethoxysilane, trihexyl(tetradecyl)phosphonium decanoate and talc powder is 3.5 - 4.0 mL: 95 mL: 45 mL: 2.0 - 2.2 g: 2.0 - 2.2 g: 0.20 - 0.23 g.

4. A polyethylene composite hose according to claim 1, characterized in that, The particle size of the talc powder is 60 - 100 nm.

5. A polyethylene composite hose according to claim 1, characterized in that, The antioxidant is one of antioxidant 1010, antioxidant 1076, antioxidant 168 and antioxidant 626; the lubricant is one of magnesium stearate, calcium stearate and ethylene bisstearamide.

6. A polyethylene composite hose according to claim 1, wherein, The materials of the inner layer and the outer layer include the following components in parts by weight: 20 - 50 parts of low-density polyethylene, 20 - 50 parts of high-density polyethylene, 5 - 23 parts of linear low-density polyethylene, and 5 - 12 parts of metallocene polyethylene.

7. A polyethylene composite hose according to claim 1, wherein, The materials of the inner adhesive layer and the outer adhesive layer are adhesives, and the adhesive is maleic anhydride grafted polyethylene.

8. A polyethylene composite hose according to claim 1, characterized in that, The material of the middle layer is ethylene-vinyl alcohol copolymer.

9. A polyethylene composite hose according to claim 1, characterized in that, The thickness ratio of the inner layer, the sub-inner layer, the inner adhesive layer, the middle layer, the outer adhesive layer and the outer layer is 25 - 35: 15 - 25: 2.5 - 4.0: 2.5 - 4.0: 2.5 - 4.0: 25 - 35.

10. A method for preparing a polyethylene composite hose according to any one of claims 1-9, characterized in that, It includes the following steps: Step 1: Add the raw materials of each layer into different mixers according to the ratio for mixing respectively to obtain the mixed materials of the raw materials of each layer. Step 2: Respectively feed the mixed materials of the raw materials of each layer obtained in Step 1 into the first extruder, the second extruder, the third extruder, the fourth extruder, the fifth extruder and the sixth extruder, extrude and form, cool and solidify, cut and correct to obtain the polyethylene composite hose.

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