specification Title of Invention: Olefin Polymer Technical field [One] [Cross reference of related applications] [2] This application claims the benefit of priority based on Korean Patent Application No. 10-2017-0178329 filed on December 22, 2017, and all contents disclosed in the documents of the Korean patent application are included as part of this specification. [3] [Technical field] [4] The present invention relates to an olefin-based polymer, and more particularly, to a low-density olefin-based polymer having low hardness prepared by using two types of transition metal compound catalysts and having improved foaming properties and impact strength during compounding. Background [5] Polyolefins have excellent moldability, heat resistance, mechanical properties, hygiene quality, water vapor permeability, and appearance characteristics of molded products, and are widely used for extrusion molded products, blow molded products and injection molded products. However, since polyolefins, especially polyethylene, do not have polar groups in their molecules, they have low compatibility with polar resins such as nylon, and low adhesiveness with polar resins and metals. As a result, it has been difficult to blend polyolefins with polar resins or metals or to laminate them with these materials. Further, the molded article of polyolefin has a problem of low surface hydrophilicity and antistatic property. [6] In order to solve this problem and increase the affinity for a polar material, a method of grafting a polar group-containing monomer onto a polyolefin through radical polymerization has been widely used. However, this method has a problem of low miscibility due to poor viscosity balance between the graft polymer and the polar resin due to intramolecular crosslinking and cleavage of the molecular chain of the polyolefin during the graft reaction. In addition, there is a problem in that the appearance characteristics of the molded article are low due to a gel component generated by intramolecular crosslinking or a foreign material generated by cleavage of a molecular chain. [7] In addition, as a method of preparing an olefin polymer such as an ethylene homopolymer, an ethylene/α-olefin copolymer, a propylene homopolymer or a propylene/α-olefin copolymer, a polar monomer is copolymerized under a metal catalyst such as a titanium catalyst or a vanadium catalyst. Method was used. However, when a polar monomer is copolymerized using the above metal catalyst, there is a problem in that the molecular weight distribution or composition distribution is wide, and the polymerization activity is low. [8] In addition, as another method, a method of polymerizing in the presence of a metallocene catalyst made of a transition metal compound such as zircononocene dichloride and an organoaluminum oxy compound (aluminoxane) is known. When a metallocene catalyst is used, a high molecular weight olefin polymer is obtained with high activity, and the resulting olefin polymer has a narrow molecular weight distribution and a narrow composition distribution. [9] In addition, a metallocene compound having a ligand of a non-crosslinked cyclopentadienyl group, a crosslinked or non-crosslinked bis indenyl group, or an ethylene bridged unsubstituted indenyl group/fluorenyl group is used as a catalyst to prepare a polyolefin containing a polar group. As a method, a method of using a metallocene catalyst is also known. However, these methods have a disadvantage of very low polymerization activity. For this reason, although a method of protecting a polar group by a protecting group is being carried out, when introducing a protecting group, there is a problem that the process becomes complicated because the protecting group must be removed again after the reaction. [10] Ansa-metallocene compound is an organometallic compound comprising two ligands connected to each other by a bridge group, and the rotation of the ligand is prevented by the bridge group, and the activity of the metal center and The structure is determined. [11] Such ansa-metallocene compounds are used as catalysts in the production of olefin-based homopolymers or copolymers. In particular, it is known that an ansa-metallocene compound containing a cyclopentadienyl-fluorenyl ligand can produce a high molecular weight polyethylene, through which the microstructure of polypropylene can be controlled. have. [12] In addition, an ansa-metallocene compound containing an indenyl ligand is known to be capable of producing a polyolefin having excellent activity and improved stereoregularity. [13] As such, various studies have been conducted on ansa-metallocene compounds that can control the microstructure of olefin-based polymers while having higher activity, but the degree is still insufficient Detailed description of the invention Technical challenge [14] An object to be solved of the present invention is to provide a low-density olefin-based polymer having low hardness and improved foaming properties and impact strength during compounding, prepared using two kinds of transition metal compound catalysts. Means of solving the task [15] In order to solve the above problem, the present invention [16] (1) the density (d) is 0.850 g/cc to 0.865 g/cc, (2) the melt index (Melt Index, MI, 190° C., 2.16 kg load condition) is 0.1 g/10 min to 3.0 g/10 min. , (3) melting temperature (Tm) is 10 ℃ to 100 ℃, (4) hardness (H, Shore A), density (d) and melting temperature (Tm) satisfies the following equation (1), olefin-based polymer Provides. [17] [Equation 1] [18] H=1293×d+A [19] In Equation 1, A satisfies Equation 2 or 3 below. [20] [Equation 2] [21] Tm×(0.855×Tm-62)8%), the hardness decreases and the impact strength increases during compounding, but it is a very difficult technique to increase the SF content by more than a certain level at the same density, and even if the SF content is increased as in Comparative Example 1, The molecular weight is lowered, which reduces the impact strength and adversely affects blocking. The copolymer of the example has excellent impact strength and blocking by maintaining a high molecular weight of the fraction while maintaining a high SF content. Claims [Claim 1] (1) the density (d) is 0.850 g/cc to 0.865 g/cc, (2) the melt index (Melt Index, MI, 190° C., 2.16 kg load condition) is 0.1 g/10 min to 3.0 g/10 min. , (3) melting temperature (Tm) is 10 ℃ to 100 ℃, (4) hardness (H, Shore A), density (d) and melting temperature (Tm) satisfying the following equation (1), olefin-based polymer : [Equation 1] H=1293×d+A In Equation 1, A satisfies Equation 2 or 3 below. [Equation 2] Tm×(0.855×Tm-62)