SHAPE MEMORY POLYMER STRUCTURE HAVING LATTICE FRAME TECHNICAL FIELD The present invention is directed to a shape memory polymer structure having a lattice frame, and more specifically, to a shape memory polymer structure having lattice frames, in which polymers having shape memory properties are used as structural materials and thus the shape of a structure can be appropriately changed by controlling temperature, and also the inside of the structure is formed with lattice frames and so elastic force is further improved and deformation of the structure is easily carried out.

PRIOR ART The shape memory polymer adopts a three dimensional shape imposed under a condition a and even when changed to a quite different shape under another condition b, restores the original shape under a condition c.

In general, there have been known shape memory polymers, which are composed of a shape memory polymer comprising crystalline polymer crosslinked substances, a shape memory polymer having remarkably high molecular weight, a shape memory polymer consisting of thermoplastic block copolymers, or a blend of crystalline polyalkylene polymers and rubbery polymers.

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a shape memory polymer structure having lattice frames, not only easily changeable in its shape of structure within a range of 50-100 °C, and manufactured without performing a vulcanization or high temperature molding process, but also having improved elastic force,

thereby easily changing shape of the structure owing to internal lattice frames, thereby being used as various industrial materials.

In accordance with an embodiment of the present invention, there is provided a lattice frame-containing shape memory polymer structure, which consists of shape memory polymer materials and is integratedly formed with a four-sides closed outer wall and partitions comprising large numbers of lattice frames therein.

BRIEF DESCRIPTION OF THE DRAWINGS The above object of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a perspective view showing a primarily molded shape memory structure having lattice frames according to the present invention; Fig. 2 is a front view of the shape memory structure shown in Fig. 1; Fig. 3 is a view showing an elongated form of the shape memory structure of the present invention; Fig. 4 is a view showing a compressed form of the shape memory structure of the present invention; and Fig. 5 is a view showing a twisted form of the shape memory structure of the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION According to the present invention, shape memory polymer structures having many lattice frames therein, prepared by use of shape memory polymer materials, are elongated or compressed in a range of about 50-100 °C to obtain altered shape structures, which are then cooled to a temperature at which the phase

of shape memory polymers are non-plastic, thus the altered shape being fixed.

Subsequently, the altered structure is warmed to a temperature which restores the plasticity of shape memory polymers, thereby easily restoring the initial shapes.

With reference to Fig. 1, there is shown a primarily molded shape memory structure having lattice frames of the present invention. As can be seen in this drawing, a quadrangular outer wall 10 in which four sides are closed is integratedly molded with partitions 11 comprising lattice frames within the outer wall 10. A front view of such structure is presented in Fig. 2.

The primarily molded structure is deformable in various forms, for example, in an elongated form, as seen in Fig. 3; a compressed form, as in Fig. 4; and a twisted form, as shown in Fig. 5, by controlling temperature.

In the shape memory polymer structure having lattice frames of the present invention, the primarily molded structure is formed as a honeycombed structure, the cells formed in a lengthwise direction when fixed in the elongated state, or in a widthwise direction when fixed by compressing the structure, by controlling temperature.

To the inner walls of the structural lattice frames, polymer materials having various properties can be coated and thus physical, chemical, electrical, and magnetic properties can be selectively controlled. In addition, the structure can be molded in an internally spaced form or an airtight form, depending on the pressures to be applied.

Therefore, when the shape memory structure having lattice frames are used to make an outer sole of shoes for prevention of slipping while mountain- climbing or fishing, the shape of the structures can be freely changed so that the articles having various sizes and shapes can be prepared by a mold having lattice form.

As well, because body weight is transferred to lattice frames-partitions of the structure constituting the outer sole of shoes when the wearer takes a step, the

structure having lattice frames has larger traction than a planar frame-containing structure, thus further improving a slipping-prevention performance.

In the case of applying the structure to an inner sole of shoes, the structure can memorize different shapes of each foot, regardless of the size of shoes, so that comfortable walking shoes can be prepared.

Meanwhile, the shape of lattice frames of the present invention may be variously formed, for instance, a triangle, a hexagon (a honeycomb type), an octagon and so on, in addition to a quadrangle. It is preferred that the shape memory polymers which can be made plastic in the temperature range of about 50- 100 °C are used.

In the case of using the lattice frame-containing shape memory structure as industrial materials, the resistance to compression is largely enhanced due to the partitions constituting the lattice frame, so that the structure of the present invention may be utilized as means to control space intervals of any supporting- structures having high compression strength.

Conventionally, when the primary structure having fixed shapes is applied to various designs or curved surfaces of desired products, the structure is again molded or cut, requiring work, whereby the working period of time is delayed and also economic burden arises. However, by using the lattice frame-containing shape memory structure of the present invention, the shape of prepared structure can be changed by only temperature control without the need of another molding or cutting process, thus shortening the working period of time and reaping economic benefit.

In the present invention, the shape memory structure having lattice frames can be applied to a cup of female brassiere, because it can be easily altered in its form to suit different breast sizes of females. Additionally, resistance to compression is generated because of lattice frame-comprising partitions, so that the shape of the structure is not changed by external forces.

The present shape memory structure having lattice frames can be utilized as an abrasive material in the fields of various industries, by molding the structure in a spherical form, filling the lattice with diamond, alumina and silundum which are abradants, and then compressing the structure, as shown in Fig. 4.

In addition, the lattice frame-containing shape memory structure comprises materials which can be freely changed in their shape in the temperature range of 50-100 °C and restore their initial shape by controlling temperature, so that the present structure can be variously used in industrial and other fields.

INDUSTRIAL APPLICABILITY As mentioned above, the lattice frame-containing shape memory polymer structure of the present invention can be secondarily variously altered in shape, by controlling temperature, and then the secondary structure can be easily restored to the original structure shape. The shape memory polymer structure has the advantage of improved elasticity because of the lattice frames, and thus can be applied to tires, shoes for slipping-prevention, various industrial materials, or industrial appliances.

The present invention has been described in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.