Immobilisation device

Abstract

The present invention relates to a template for a positioning, fixation, mobilization or immobilization device, wherein the template comprises a sheet of a thermoplastic material, wherein the thermoplastic material comprises between 3.0 and 95.0 wt. % of a poly-?-caprolactone polymer, preferably a poly-?-caprolactone homopolymer, and at least 5.0 wt. % of at least one second polymer material with a melting temperature of between 40 and 85? C., wherein the at least one second polymer material is selected from the group of one or more of a polyalkenamer or a thermoplastic linear polyurethane which contains as a polyol a poly ?-caprolactone or a polyester polyol, wherein the poly-?-caprolactone polymer and the second thermoplastic material are cross-linked.

Claims

1. A template for a positioning, fixation, mobilization or immobilization device, wherein the template comprises a sheet of an at least partially cross-linked thermoplastic material, wherein the thermoplastic material comprises: between 3.0 and 95.0 wt. % of a poly-?-caprolactone polymer, wherein the poly-?-caprolactone polymer has a number average molecular weight Mn of at least 50.000 g/mole and of maximum 90.000 g/mole, and at least 5.0 wt. % of at least one second thermoplastic polymer material with a melting temperature of between 40 and 85? C., wherein the at least one second thermoplastic polymer material is one or more of a thermoplastic polyalkenamer or a thermoplastic linear polyurethane based on a poly-?-caprolactone polyol or a polyester polyol; wherein the poly-?-caprolactone polymer and the second thermoplastic polymer material are cross-linked.

2. A template according to claim 1, wherein the poly-?-caprolactone polymer is present in the thermoplastic material in a concentration of between 15.0 and 90.0 wt.

3. A template according to claim 1, wherein the thermoplastic linear polyurethane is present in the thermoplastic material in a concentration of between 5.0 and 97.0 wt. %.

4. A template according to claim 1, wherein the thermoplastic polyalkenamer is present in the thermoplastic material in a concentration of 5 wt. % up to 20.0 wt. %.

5. A template according to claim 1, wherein the poly-?-caprolactone polymer has a melting temperature of between 40 and 70? C.

6. A template according to claim 1, wherein the poly-?-caprolactone polymer contains between 35 and 70 wt. % of crystalline poly-?-caprolactone with respect to the weight of the poly-?-caprolactone polymer.

7. A template according to claim 1, wherein the poly-?-caprolactone polyol units of the thermoplastic linear polyurethane have a number average molecular weight Mn of at least 1000 g/mole and maximum 2500 g/mole.

8. A template according to claim 1, wherein the thermoplastic linear polyurethane based on a poly-?-caprolactone polyol has a melting temperature of between 40 and 70? C.

9. A template according to claim 1, wherein the thermoplastic material has a molding time of between 1 and 15 minutes after having been heated to the melting temperature.

10. A template according to claim 1, wherein the thermoplastic polyalkenamer is a polyoctenomer, having a melting temperature ranging between 5 and 80? C.

11. A method for producing a template according to claim 1, comprising: preparing the thermoplastic material by blending the poly-?-caprolactone polymer and the at least one second thermoplastic polymer material with a melting temperature of between 40 and 85? C., blending the thermoplastic material with a cross-linking initiator, wherein the cross-linking initiator is provided in an amount of 0.2-10.0 wt. % based on the weight of the thermoplastic material; forming the thermoplastic material into a sheet; and subjecting the sheet to cross-linking to at least partially cross-link the thermoplastic material.

12. A method according to claim 11, wherein the template is perforated in advance of being subjected to cross-linking.

13. A method according to claim 11, wherein cross-linking involves a first step of partial cross-linking of the thermoplastic material after it has been shaped into a sheet, and a second step of further cross-linking before the sheet of thermoplastic material is shaped into an immobilization device.

14. A method for shaping a template according to claim 1 to a part of a body of a living subject that needs to be positioned, mobilized or immobilized, wherein a thermoplastic material is heated to a temperature of between 40 and 85? C., positioned on the body part, shaped to conform to the contours of the body part, and left to cool.

15. An immobilization device comprising a template according to claim 1 molded into a shape that permits immobilization of a desired body part.

16. A method for producing an immobilization device, wherein a template according to claim 1 is heated to a temperature between 40 and 85? C., positioned on a body part that needs to be positioned, mobilized or immobilized, shaped to conform to the contours of the body part, and left to cool.

17. A sheet of an at least partially cross-linked thermoplastic material, wherein the thermoplastic material comprises; between 3.0 and 95.0 wt. % of a poly-?-caprolactone polymer, wherein the poly-?-caprolactone polymer has a number average molecular weight Mn of at least 50.000 g/mole and a maximum 90.000 g/mole, and at least 5.0 wt. % of at least one second thermoplastic polymer material with a melting temperature of between 40 and 85? C., wherein the at least one second thermoplastic polymer material is one or more of a thermoplastic polyalkenamer or a thermoplastic linear polyurethane based on a poly ?-caprolactone polyol or a polyester polyol; wherein the poly-?-caprolactone polymer and the second thermoplastic polymer material are cross-linked.

18. An immobilization device comprising a sheet according to claim 17 molded into a shape that permits immobilization of a desired body part.

Description

EXAMPLE 1 AND 2

(1) Two blends were prepared of poly-?-caprolactone (PCL) with a number averaged molecular weight Mn of about 50000 and a melting range of between 58 and 60? C., and a polyoctenamer (POM) with a trans-double bond content of nearly 80%, a molecular weight of 90000, a melting point of 54? C.,
in the amounts indicated in the table 1 below.
The blend further contained 1.0 wt. % of triallyl isocyanurate as a cross-linking initiator. The triallyl isocyanurate was incorporated into the PCL and its amount is included in the amount of PCL in table 1.

(2) The blend was mixed in a twin screw extruder at 130? C., cooled and formed into granules. An amount of granules was heated to a temperature of 130? C. and press molded into a thermoplastic sheet with a thickness of 2.0 mm and a size of 250?250 mm, using an hydraulic press of Agila model PE30.

(3) The thermoplastic sheet was subjected to cross-linking by subjecting it to irradiation doses of 5 KGy. The properties of the cross-linked sheet are summarized in Table 1 below.

(4) TABLE-US-00001 TABLE 1 3-Point- Time of isometric crystallisation Bending Max. Flexural PCL POM Crystallistion 50% Full contraction Modulus Ex. wt. %* wt. % onset* crystallisation* crystallisation** load (N) (MPa) 1 95 5 2 m 15 s 5 m 10 s 19 m 46.9 491 2 85 15 2 m 30 s 5 m 45 s 21 m 42.18 444 *the poly-?-caprolactone contained 1.5 wt. % of the usual additives **in minutes (m) and seconds (s)

(5) The memory, measured after reheating of samples which had been subjected to stretching, with a degree of stretching of 70% at 65? C., was almost 100% for each of the samples. This means that the samples which had been subjected to 70% stretching at 65? C., followed by cooling to room temperature in the stretched condition while being fixed to a support member, and which were thereafter reheated to 65? C., returned to their initial shape upon coolingalso when not fixed to a support member.

(6) From table 1 it can be concluded that by incorporation of the polyoctenamer into the thermoplastic poly ?-caprolactone, the period of time which elapsed before crystallization started and that the time available up to full crystallization of the material, could be increased. As a result, more time remains available for the moulding of a sheet of thermoplastic material according to the invention, onto a body part to be immobilized, into a desired shape.

(7) As can be understood from table 1, with an increasing degree of substitution of poly-?-caprolactone, the material of the thermoplastic sheet was sensed by the test persons as softer to the skin.

EXAMPLE 3-4 AND COMPARATIVE EXAMPLE A

(8) A blend was prepared of varying amounts of poly-?-caprolactone (PCL) with a number averaged molecular weight Mn of about 50000 and a melting range of between 58 and 60? C., and a linear thermoplastic polyurethane (PU), which contained poly-?-caprolactone units as a polyol with a melting range of 65-71? C.,
in the amounts indicated in the table 2 below. The blend further contained about 1 wt. % of triallyl isocyanurate as a cross-linking agent. The triallyl isocyanurate was incorporated into the PCL and its amount is included in the amount of PCL in table 1.

(9) The blend was subjected to melt mixing with a twin screw extruder at 130? C., thereafter cooled and granulated. The thus obtained granules were heated to a temperature of 130? C., and press molded into a sheet with a thickness of 2.0 mm and a size 250?250 mm using an hydraulic press of Agila model PE30. The thermoplastic sheet was subjected to cross-linking by subjecting it to ?-irradiation. of 5 KGy.

(10) The properties of the cross-linked sheet are summarized in table 2 below.

(11) From table 2 it can be concluded that by incorporation of polyurethane into the poly-?-caprolactone, the time available up to the start of the crystallization, as well as the time available up to full crystallization of the material increased. As a result, more time remains available for the moulding of a sheet onto the body part to be immobilized, into a desired shape.

(12) With an increasing degree of substitution of PCL, the material of the thermoplastic sheet was sensed by the test persons as softer to the skin.

(13) TABLE-US-00002 TABLE 2 Time of isometric crystallisation Crystallisation Maximum contraction Ex. PCL wt. % PU wt. % onset (min s) load (N) A 100 0 1 m 30 s 50 3 90 10 2 m 00 s 47 4 3 97 3 m 30 s 22 * the poly-?-caprolactone contained 1.5 wt. % of the usual additives ** in minutes (m) and seconds (s)

EXAMPLE 5-6

(14) A 3 points fixation mask was cut from a perforated sheet that had been produced from the mixtures of polyoctenamer and poly-?-caprolactone of example 1 and 2. The mask was heated to a temperature of 65? C. and molded on a dummy head. The fixation/shrinkage force Fv was measured during cooling of the mask after 30 min and 24 h by using the method described in a patent application BE 1015081. The results are presented in Table 3.

(15) From Table 3 it can be concluded that by incorporation of the polyoctenamer the shrinkage force of immobilization mask decreased which will increases the comfort of the patient.

(16) TABLE-US-00003 TABLE 3 Mask - Shrinkage Force (Fv) Fv (30 min) Fv (24 hours) Ex. PCL wt. % POM wt. % (N) (N) 5 95 5 123 190 6 85 15 110 163 * the poly-?-caprolactone contained 1.5 wt. % of the usual additives

EXAMPLE 7-8 AND COMPARATIVE EXAMPLE B

(17) A 3 points fixation masks was cut from a maximally perforated sheet produced from a thermoplastic material that contained both poly-?-caprolactone and a linear polyurethane with poly-?-caprolactone diol. The mask was heated or activated at 65? C. and molded on a dummy head. The fixation/shrinkage force Fv was measured during cooling of the mask after 30 min and 48 hours. The measured test results are presented in Table 4.

(18) TABLE-US-00004 TABLE 4 Properties of 3 points fixation masks based on composition of PCL and PU. Shrink and Stability Fv (30 min) Fv (48 hours) Ex. PCL wt % PU wt. % (N) (N) B 100 0 75 170 7 85 15 60 150 8 70 30 50 120 * the poly-?-caprolactone contained 1.5 wt. % of the usual additives
From Table 4 it can be concluded that by incorporation of the linear PU containing poly-?-caprolactone diol, the shrinkage force Fv of the immobilization mask could be reduced, which will increases the comfort of the patient.