阅读说明：本技术 一种高抗拉透明拉伸膜 (High-tensile transparent stretch film ) 是由 刘庆双 于 2019-09-26 设计创作，主要内容包括：本发明公开了一种高抗拉透明拉伸膜,该拉伸膜包括内层和外层,内层的重量占膜总重的20～30％,外层的重量占膜总重的70％～80％,内层的厚度为膜总厚度的20～30％,外层的厚度为膜总厚度的70％～80％,内层的制备原料包括占重比高于99％的线性低密度聚乙烯及占重比低于1％的添加剂；外层的制备原料包括占重比为10～30％的低密度聚乙烯、占重比为70％～90％的线性低密度聚乙烯及占重比低于1％的添加剂。本发明拉伸膜在保证高拉伸强度、断裂伸长率、冲击强度和抗刺强度的情况下,提高了其透明度。(The invention discloses a high-tensile-strength transparent stretch film, which comprises an inner layer and an outer layer, wherein the weight of the inner layer accounts for 20-30% of the total weight of the film, the weight of the outer layer accounts for 70-80% of the total weight of the film, the thickness of the inner layer accounts for 20-30% of the total thickness of the film, the thickness of the outer layer accounts for 70-80% of the total thickness of the film, and preparation raw materials of the inner layer comprise linear low-density polyethylene accounting for more than 99% of the weight ratio and an additive accounting for less than 1% of the weight ratio; the preparation raw materials of the outer layer comprise 10-30% of low density polyethylene, 70-90% of linear low density polyethylene and less than 1% of additive. The transparency of the stretched film is improved under the condition of ensuring high tensile strength, elongation at break, impact strength and puncture resistance.)

1. A high tensile transparent stretch film is characterized in that: the stretched film comprises an inner layer and an outer layer, wherein the weight of the inner layer accounts for 20-30% of the total weight of the film, the weight of the outer layer accounts for 70-80% of the total weight of the film, the thickness of the inner layer accounts for 20-30% of the total thickness of the film, the thickness of the outer layer accounts for 70-80% of the total thickness of the film, and the inner layer and the outer layer are sequentially arranged in a film body,

the raw materials for preparing the inner layer comprise linear low-density polyethylene accounting for more than 99% by weight and additives accounting for less than 1% by weight; the outer layer is prepared from the raw materials of 10-30% by weight of low-density polyethylene, 70-90% by weight of linear low-density polyethylene and less than 1% by weight of additive.

2. The high tensile transparent stretch film according to claim 1, wherein: the preparation components of the linear low-density polyethylene comprise 90-94% of ethylene, 6-10% of alpha-olefin and less than 1% of catalyst; the preparation components of the low-density polyethylene comprise 85-90% of ethylene, 10-15% of alpha-olefin and less than 1% of catalyst.

3. The high tensile transparent stretch film according to claim 2, wherein: the alpha-olefin is one of octene, butene, hexene and tetramethylpentene, wherein octene and ethylene are copolymerized in a solution phase reactor, and butene, hexene and tetramethylpentene and ethylene are copolymerized in a gas phase reactor.

4. The high tensile transparent stretch film according to claim 2, wherein: the catalyst comprises one or more of a ziegler-natta type catalyst, a metallocene catalyst, a chromium based catalyst.

5. The high tensile transparent stretch film according to claim 1, wherein: the additive comprises an antioxidant accounting for 30 percent of the total weight of the additive, an ultraviolet absorbent accounting for 30 percent of the total weight of the additive and a slip agent accounting for 40 percent of the total weight of the additive.

6. The high tensile transparent stretch film according to claim 1, wherein: the thickness of the inner layer is 0.004 mm-0.009 mm, and the thickness of the outer layer is 0.014 mm-0.024 mm.

7. The high tensile transparent stretch film according to claim 1, wherein: the elongation at break of the stretched film in the longitudinal direction is 441% -642%, and the elongation at break of the stretched film in the transverse direction is 512% -776%; the longitudinal tensile strength of the stretch film is 13-18.28N/25 mm, and the transverse tensile strength of the stretch film is 6.75-11N/25 mm; the dart impact strength of the stretched film is 70-80 g.

Technical Field

The invention relates to the technical field of films, in particular to a high-tensile transparent stretch film.

Background

The stretch film (also called winding film) has higher tensile strength and tearing resistance and good self-adhesion, so that the stretch film can wrap an object into a whole. Stretched films are commonly used in agriculture, such as greenhouse films, mulching films, packaging films, and the like, and conventional stretched films mainly include films made of Linear Low Density Polyethylene (LLDPE) and films made of Low Density Polyethylene (LDPE), as the LLDPE has a molecular structure containing short branched chains but not long branched chains of the LDPE molecular structure, the LLDPE has more outstanding performance than LDPE, mainly represented by that the tensile strength and the elongation at break are 40-50% higher than that of LDPE, in addition, the impact strength and the puncture strength are also superior to that of LDPE, because of the special physical and mechanical properties of LLDPE, most of the prior stretched films are made of the LLDPE instead of the LDPE, however, the haze value of the pure LLDPE processed film is high, and the high crystallinity thereof causes high surface roughness and low transparency of the film, so that the inner situation cannot be clearly seen when the film is used, and thus the prior art needs to be improved.

Disclosure of Invention

Aiming at the defects in the prior art, the technical problem to be solved by the invention is to provide a high-tensile transparent stretch film.

In order to solve the technical problem, the invention is realized by the following scheme: a high tensile transparent stretch film is characterized in that: the stretched film comprises an inner layer and an outer layer, wherein the weight of the inner layer accounts for 20-30% of the total weight of the film, the weight of the outer layer accounts for 70-80% of the total weight of the film, the thickness of the inner layer accounts for 20-30% of the total thickness of the film, the thickness of the outer layer accounts for 70-80% of the total thickness of the film, and the inner layer and the outer layer are sequentially arranged in a film body,

the raw materials for preparing the inner layer comprise linear low-density polyethylene accounting for more than 99% by weight and additives accounting for less than 1% by weight; the outer layer is prepared from the raw materials of 10-30% by weight of low-density polyethylene, 70-90% by weight of linear low-density polyethylene and less than 1% by weight of additive.

Further, the preparation components of the linear low-density polyethylene comprise 90-94% of ethylene, 6-10% of alpha-olefin and less than 1% of catalyst; the preparation components of the low-density polyethylene comprise 85-90% of ethylene, 10-15% of alpha-olefin and less than 1% of catalyst.

Further, the alpha-olefin is one of octene, butene, hexene and tetramethylpentene, wherein octene and ethylene are copolymerized in a solution phase reactor, and butene, hexene and tetramethylpentene and ethylene are copolymerized in a gas phase reactor.

Further, the catalyst comprises one or more of a ziegler-natta type catalyst, a metallocene catalyst, a chromium based catalyst.

Further, the additive comprises an antioxidant accounting for 30 percent of the total weight of the additive, an ultraviolet absorbent accounting for 30 percent of the total weight of the additive and a slip agent accounting for 40 percent of the total weight of the additive.

Furthermore, the thickness of the inner layer is 0.004 mm-0.009 mm, and the thickness of the outer layer is 0.014 mm-0.024 mm.

Further, the elongation at break of the stretched film in the longitudinal direction is 441% -642%, and the elongation at break of the stretched film in the transverse direction is 512% -776%; the longitudinal tensile strength of the stretch film is 13-18.28N/25 mm, and the transverse tensile strength of the stretch film is 6.75-11N/25 mm; the dart impact strength of the stretched film is 70-80 g.

Compared with the prior art, the invention has the beneficial effects that: the stretch film is formed by co-extrusion blow molding of two layers of different raw materials, wherein the inner layer is mainly made of Linear Low Density Polyethylene (LLDPE), the outer layer is mainly made of Linear Low Density Polyethylene (LLDPE) and a small amount of Low Density Polyethylene (LDPE), the film thickness of the inner layer is about 20-30% of the total film thickness, the LLDPE of the inner layer ensures higher tensile strength, elongation at break, impact strength and puncture resistance of the film, and when a small amount of LDPE is added into the outer layer, the mechanical property of the film is not greatly reduced, but the transparency is obviously improved.

Detailed Description

The following detailed description of the preferred embodiments of the present invention is provided to enable those skilled in the art to more readily understand the advantages and features of the present invention and to clearly and unequivocally define the scope of the present invention.