A flexible grass filament and a method of making the same

Abstract

This invention discloses a flexible grass fiber and its preparation method. The flexible grass fiber, by weight, comprises the following components: 100 parts linear low-density polyethylene, 10-30 parts soft material, 1-3 parts processing aids, and, by weight percentage, 4-8% coloring masterbatch. The soft material, by weight percentage, comprises the following components: 30-40% SEBS, 50-80% polyolefin oil, 2-10% polypropylene, 0.03-0.08% antioxidant, with the balance being a dispersant. This invention improves the flexibility, comfort, and realism of the grass fiber.

Description

Technical Field

[0001] This invention belongs to the field of artificial grass fiber technology, specifically relating to a flexible grass fiber and its preparation method. Background Technology

[0002] Due to factors such as geographical location, natural conditions, and economic status, and the objective need for roofs and other facilities in a significant number of natural grass courts, the installation and maintenance of natural turf is quite difficult. In contrast, artificial turf shows a significant advantage. After a long period of development, artificial turf technology has matured considerably, with many technical indicators approaching those of natural grass. However, there is a significant difference in feel between artificial and natural grass. The main raw material for artificial turf is polyolefin. Traditional polyolefin products have a hard surface, giving them a hard, cheap plastic feel, and the current user experience of artificial turf is not pleasant. Currently, consumers are seeking comfort and realism in artificial turf, necessitating the development of a new, flexible turf fiber. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a flexible grass fiber and its preparation method, thereby improving the flexibility, comfort, and realism of the grass fiber.

[0004] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, the present invention provides a flexible grass fiber, comprising, by weight parts: 100 parts of linear low-density polyethylene, 10-30 parts of soft material, 1-5 parts of processing aid, and, by weight percentage, 4-8% of coloring masterbatch.

[0006] The soft material comprises the following components by mass percentage: SEBS 30-40%, polyolefin oil 50-80%, polypropylene 2-10%, antioxidant 0.03-0.08%, with the remainder being dispersant.

[0007] Preferably, the polypropylene is homopolymer polypropylene with a melt index of 20-30 g / 10 min (230℃ / 2.16 kg).

[0008] Preferably, SEBS is a hydrogenated styrene-ethylene-butene-styrene block copolymer, wherein the styrene content is 30-40% and the hardness is 50-60A.

[0009] Preferably, the dispersant is polyethylene wax.

[0010] Preferably, the processing aids include antioxidants, slip agents, and light stabilizers, wherein the slip agents include one or more of silicone, erucamide, and oleamide.

[0011] Preferably, the antioxidant is a synergistic system of highly efficient hindered amines and phosphites.

[0012] Preferably, the density of linear low-density polyethylene is 0.918–0.920 g / cm³. 3 Melt index is 1-3 g / 10 min (190℃ / 2.16).

[0013] In a second aspect, the present invention provides a method for preparing flexible grass fibers, as follows:

[0014] SEBS, polyolefin oil, polypropylene, antioxidant and dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing. The extrusion temperature is 150-200℃ to obtain a soft material.

[0015] Linear low-density polyethylene, processing aids, coloring masterbatch, and soft materials are mixed evenly to obtain an intermediate mixture in the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded through multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 190-200℃.

[0016] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber.

[0017] Preferably, the stretching ratio of the intermediate straw product is 5 to 10 times.

[0018] Beneficial effects:

[0019] This invention uses a multi-layer co-extrusion process to prepare flexible grass fibers. A soft material is used as the surface layer, and modified linear low-density polyethylene is used as the intermediate support material. This results in grass fiber products with high strength, good tactile feel and compression resilience, and improved comfort and realism of the flexible grass fibers. Detailed Implementation

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, specific implementation methods of the present invention will be described below. Obviously, those skilled in the art can obtain other implementation methods based on the embodiments described below without creative effort.

[0021] The present invention provides a flexible grass fiber, which, by weight parts, comprises the following components: 100 parts of linear low-density polyethylene, 10-30 parts of soft material, 1-5 parts of processing aid, and, by weight percentage, 4-8% of coloring masterbatch.

[0022] The soft material comprises the following components by mass percentage: SEBS 30-40%, polyolefin oil 50-80%, polypropylene 2-10%, antioxidant 0.03-0.08%, with the remainder being dispersant.

[0023] In this invention, polyolefin oil has a high content in soft materials. Its main function is to modify SEBS. If the amount of polyolefin oil is less than 50%, it will affect the plasticizing effect of SEBS, thereby affecting the quality of grass fibers. If the amount of polyolefin oil is greater than 80%, the polyolefin oil is easy to precipitate, resulting in low grass fiber strength, overall softness, and even clumping under high temperature conditions during processing, making production impossible.

[0024] In this invention, linear low-density polyethylene is used as the main raw material, and its performance is improved and its flexibility is enhanced by a soft material. The soft material of this invention is distributed on the surface of the product, giving the material good compression resilience. When touched, the surface of the product can undergo slight deformation, thus having a soft touch.

[0025] In soft materials, SEBS is a hydrogenated styrene-ethylene-butene-styrene block copolymer, wherein the styrene content is 30-40% and the hardness is 50-60A.

[0026] The polypropylene is a homopolymer polypropylene with a melt index of 20-30 g / 10 min (230℃ / 2.16 kg).

[0027] The dispersant is polyethylene wax, preferably AC-6A type. The dispersant's function is to uniformly disperse solid particles or powders, preventing aggregation that could affect material properties.

[0028] In this invention, the preparation method of the soft material is as follows: SEBS, polyolefin oil, polypropylene, antioxidant and dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing, wherein the extrusion temperature is 150-200℃ to obtain the soft material.

[0029] Processing aids include antioxidants, slip agents, and light stabilizers, wherein slip agents include one or more of silicone, erucamide, and oleamide.

[0030] In this invention, soft materials are preferred. SEBS has a rubber phase, so it is necessary to use polyolefin oil to soften and plasticize SEBS in advance to facilitate subsequent processing. If SEBS, polyolefin oil, polypropylene, etc. are directly mixed with linear low-density polyethylene, the polyolefin oil cannot modify SEBS, and flexible grass fibers cannot be prepared.

[0031] Preferably, the antioxidants in the processing aids and the antioxidants in the soft materials are both highly efficient hindered amines and phosphites in a synergistic compound system.

[0032] The density of linear low-density polyethylene is 0.918–0.920 g / cm³. 3 The melt index is 1-3 g / 10 min (190℃ / 2.16), preferably Dow Chemical 5220 or 2047.

[0033] In this invention, the surface of the flexible grass fibers is provided with a multi-ribbed structure, which is formed during molding and then formed into grass fibers with high flexibility and resilience in the subsequent drawing process.

[0034] The present invention also provides a method for preparing flexible grass fibers, as follows:

[0035] Linear low-density polyethylene, processing aids, coloring masterbatch, and soft materials are mixed evenly to obtain an intermediate mixture in the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded through multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 190-200℃.

[0036] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber. The stretching ratio is 5 to 10 times, preferably 5 to 6 times.

[0037] The intermediate blend, primarily composed of linear low-density polyethylene (LLDPE), is a rigid material. The softer materials improve the rigidity of the LLDPE, enhancing its flexibility. The intermediate blend increases the softness of the flexible grass fibers and provides primary support. The softer materials, acting as the surface layer, give the flexible grass fibers a better feel and resilience.

[0038] In this invention, the strength of the flexible grass fibers is related to the draw ratio. Based on the raw materials and preparation method of the intermediate grass fiber product of this invention, a high draw ratio is used to draw the intermediate grass fiber product to obtain higher strength. If the draw ratio is small, the drawn grass fibers will have low strength and poor overall resilience; if the draw ratio is large, the obtained grass fibers will be too hard and prone to breakage during processing.

[0039] The technical solution of the present invention will be described in detail below with specific embodiments.

[0040] Example 1

[0041] By mass percentage, 30% SEBS, 63.47% polyolefin oil, 4% polypropylene, 0.03% antioxidant and 2.5% dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing. The extrusion temperature is 190℃ to obtain a soft material.

[0042] By weight, 100 parts of linear low-density polyethylene, 5 parts of processing aids, 4% coloring masterbatch, and 20 parts of soft material are mixed evenly to obtain the intermediate mixture of the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded by multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 200℃.

[0043] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretch ratio is 5.5 times.

[0044] Example 2

[0045] By mass percentage, 35% SEBS, 58.47% polyolefin oil, 4% polypropylene, 0.03% antioxidant and 2.5% dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing. The extrusion temperature is 190℃ to obtain a soft material.

[0046] By weight, 100 parts of linear low-density polyethylene, 5 parts of processing aids, 4% coloring masterbatch, and 20 parts of soft material are mixed evenly to obtain the intermediate mixture of the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded by multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 200℃.

[0047] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretching ratio is 6 times.

[0048] Example 3

[0049] By mass percentage, 40% SEBS, 53.47% polyolefin oil, 4% polypropylene, 0.03% antioxidant and 2.5% dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing. The extrusion temperature is 190℃ to obtain a soft material.

[0050] By weight, 100 parts of linear low-density polyethylene, 5 parts of processing aids, 4% coloring masterbatch, and 20 parts of soft material are mixed evenly to obtain the intermediate mixture of the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded by multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 200℃.

[0051] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretching ratio is 5 times.

[0052] Comparative Example 1

[0053] Compared to Example 1, in this comparative example, the raw materials for the soft material were directly mixed with linear low-density polyethylene.

[0054] By weight, 6 parts of SEBS, 13.1 parts of polyolefin oil, 0.8 parts of polypropylene, 0.5 parts of dispersant, 100 parts of linear low-density polyethylene, 5 parts of processing aid, and 4% of coloring masterbatch are mixed evenly and extruded to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 200℃.

[0055] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretch ratio is 5.5 times.

[0056] Comparative Example 2

[0057] Compared to Example 1, the polyolefin oil content of the soft material in this comparative example is too low.

[0058] By mass percentage, 50% SEBS, 43.47% polyolefin oil, 4% polypropylene, 0.03% antioxidant and 2.5% dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing. The extrusion temperature is 200℃ to obtain soft material 5.

[0059] By weight, 100 parts of linear low-density polyethylene, 5 parts of processing aids, 4% coloring masterbatch, and 20 parts of soft material are mixed evenly to obtain the intermediate mixture of the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded by multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 200℃.

[0060] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretch ratio is 5.5 times.

[0061] Comparative Example 3

[0062] Compared to Example 1, the polyolefin oil content of the soft material in this comparative example is too high.

[0063] By mass percentage, 5% SEBS, 88.47% polyolefin oil, 4% polypropylene, 0.03% antioxidant and 2.5% dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing. The extrusion temperature is 200℃ to obtain a soft material.

[0064] By weight, 100 parts of linear low-density polyethylene, 5 parts of processing aids, 4% coloring masterbatch, and 20 parts of soft material are mixed evenly to obtain the intermediate mixture of the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded by multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 200℃.

[0065] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretch ratio is 5.5 times.

[0066] Comparative Example 4

[0067] Compared with Example 1, in this comparative example, the flexible grass fibers were not prepared by multi-layer co-extrusion molding.

[0068] By mass percentage, 30% SEBS, 63.47% polyolefin oil, 4% polypropylene, 2.5% antioxidant and 0.03% dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing. The extrusion temperature is 200℃ to obtain a soft material.

[0069] By weight, 100 parts of linear low-density polyethylene, 5 parts of processing aids, 4% coloring masterbatch, and 20 parts of soft material are mixed evenly and extruded to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 200℃.

[0070] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretch ratio is 5.5 times.

[0071] Comparative Example 5

[0072] Compared to Example 1, a low stretching ratio was used in this comparative example.

[0073] By mass percentage, 30% SEBS, 63.47% polyolefin oil, 4% polypropylene, 0.03% antioxidant, and 2.5% dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding, and pelletizing. The extrusion temperature is 200℃ to obtain a soft material.

[0074] By weight, 100 parts of linear low-density polyethylene, 5 parts of processing aids, 4% coloring masterbatch, and 20 parts of soft material are mixed evenly to obtain the intermediate mixture of the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded by multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 190℃.

[0075] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretch ratio is 3.5 times.

[0076] Comparative Example 6

[0077] Compared to Example 1, a high stretching ratio was used in this comparative example.

[0078] By mass percentage, 30% SEBS, 63.47% polyolefin oil, 4% polypropylene, 0.03% antioxidant, and 2.5% dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding, and pelletizing. The extrusion temperature is 200℃ to obtain a soft material.

[0079] By weight, 100 parts of linear low-density polyethylene, 5 parts of processing aids, 4% coloring masterbatch, and 20 parts of soft material are mixed evenly to obtain the intermediate mixture of the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded by multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 190℃.

[0080] The intermediate product of grass fiber is stretched to prepare a layer of grass fiber, which is then shaped and dried to obtain flexible grass fiber, wherein the stretch ratio is 11 times.

[0081] The comparison results of grass fiber performance in Examples 1-3 and Comparative Examples 1-6 are shown in the table below:

[0082]

[0083] According to the test data, the grass fibers obtained by directly mixing the soft material raw materials with linear low-density polyethylene in Comparative Example 1 have significantly lower performance than the grass fibers obtained in this invention. In Comparative Example 4, where the soft material was mixed with polyethylene without multi-layer co-extrusion to form the grass fibers, the tensile strength performance was significantly inferior to that of the grass fibers in this invention. This invention uses multi-layer co-extrusion to form the grass fibers, resulting in grass fibers with both high strength and good tactile feel and compression resilience. The test results of Comparative Examples 2 and 3 show that the polyolefin oil content of the soft material also has a certain impact on the grass fiber performance. Even when using multi-layer co-extrusion, high polyolefin oil content affects the tensile strength of the grass fibers, while low polyolefin oil content affects the elongation at break. The test results of Comparative Examples 5 and 6 show that the draw ratio also has a significant impact on the grass fiber performance, especially with a high draw ratio, which significantly reduces the grass fiber performance.

[0084] The embodiments provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention, and the descriptions of the embodiments above are only for the purpose of helping to understand the core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing flexible grass fibers, characterized in that, The flexible straw fibers, by weight, include the following components: 100 parts of linear low-density polyethylene, 10 to 30 parts of soft material, 1 to 3 parts of processing aids, and, by weight percentage, 4 to 8% of coloring masterbatch. The soft material comprises the following components by mass percentage: SEBS 30-40%, polyolefin oil 50-63.47%, polypropylene 2-10%, antioxidant 0.03-0.08%, with the remainder being dispersant; The preparation method includes the following steps: SEBS, polyolefin oil, polypropylene, antioxidant and dispersant are mixed evenly and fed into a twin-screw extruder for co-extrusion, stranding and pelletizing. The extrusion temperature is 150-200℃ to obtain a soft material. Linear low-density polyethylene, processing aids, coloring masterbatch, and soft materials are mixed evenly to obtain an intermediate mixture in the middle part. The soft material is used as the surface material. The intermediate mixture and the surface material are extruded and molded through multi-layer co-extrusion to form a grass fiber intermediate product with a multi-ribbed structure. The extrusion temperature is 190-200℃. The intermediate product of grass fiber is stretched to prepare a layer of grass fiber with a stretch ratio of 5 to 10 times, and then shaped and dried to obtain flexible grass fiber.

2. The method for preparing flexible grass fibers according to claim 1, characterized in that, Polypropylene is homopolymer polypropylene, and its melt index is 20-30 g / 10min under the conditions of a test temperature of 230℃ and a load of 2.16 kg.

3. The method for preparing flexible grass fibers according to claim 1, characterized in that, SEBS is a hydrogenated styrene-ethylene-butene-styrene block copolymer, wherein the styrene content is 30-40% and the hardness is 50-60A.

4. The method for preparing flexible grass fibers according to claim 1, characterized in that, The dispersant is polyethylene wax.

5. The method for preparing flexible grass fibers according to claim 1, characterized in that, Processing aids include antioxidants, slip agents, and light stabilizers, wherein slip agents include one or more of silicone, erucamide, and oleamide.

6. The method for preparing flexible grass fibers according to any one of claims 1-5, characterized in that, Antioxidants are a highly efficient synergistic system of hindered amines and phosphites.

7. The method for preparing flexible grass fibers according to claim 1, characterized in that, The density of linear low-density polyethylene is 0.918–0.920 g / cm³. 3 Under test conditions of 190℃ and 2.16 kg load, the melt index was 1-3 g / 10 min.

8. The method for preparing flexible grass fibers according to claim 1, characterized in that, The stretching ratio of the intermediate straw fiber product is 5 to 6 times.

9. A type of flexible grass fiber, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

Images