WO2000010621A1

WO2000010621A1 - A multi-micro pore sheet for recovering human body, and a process for preparing the same

Info

Publication number: WO2000010621A1
Application number: PCT/KR1999/000473
Authority: WO
Inventors: Byung Moo Min; Sun Woong Choi; Hak Yong Kim; Keun Sung Park
Original assignee: P & M Co., Ltd.
Priority date: 1998-08-21
Filing date: 1999-08-21
Publication date: 2000-03-02

Abstract

The present invention relates to a multi-micro pore sheet for recovering human body characterized by the composition of biodegradable polymer and its low moisture content of less than 100 ppm. The multi-micro pore sheet for recovering human body of the present invention is prepared as follows: (i) prepare a multi-micro pore sheet by piling up of woven fabric, knitted fabric, chopped braid or non-woven fabric made of biodegradable staples or filaments more than 1 layers, or by using membrane of biodegradable polymer or powder of biodegradable polymer (ii) perform heat treatment of prepared multi-micro pore sheet under dry air or nitrogen atmosphere, and (iii) reiterate the process of nitrogen substitution and vacuum treatment after sterilization with ethylene oxide or η-ray.

Description

A MULTI-MICRO PORE SHEET FOR RECOVERING HUMAN BODY,

AND A PROCESS FOR PREPARING THE SAME

TECHNICAL FIELD

The present invention relates to a multi-micro pore sheet for

recovering human body and a process for preparing the same.

The said Multi— micro pore sheet for recovering human body is

used as a prop for the operations such as recovering facial cranium

fracture, recovering eye socket fracture, recovering concha fracture,

auxiliary nasal cavity, and recovering scaffold tissue.

The object of the present invention is to provide a multi-micro

pore sheet for recovering human body and a process for preparing the

same characterized by the less transposition or secession in the human

body; its role as prop for the growth of fibrous blood vessel and the

complete cure of the fracture; and no necessity for the another

removing operation after the complete of medical treatment for fracture

since it is biodegradable in the human body. DESCRIPTION OF THE PRIOR ART

To date, it has been widely used that the multi— micro pore sheet

made of such non biodegradable polymer as polyethylene, polyester or

₅ polytetrafluorethylene as multi-micro pore sheet for recovering human

body. Since the former multi— micro pore sheet does not decompose in

the human body, it is necessary to remove it after the completion of

medical cure. If the multi-micro pore sheet is not removed and

remained in the human body, it irritates the body tissues unnecessarily

1₀ or makes difficult for an another operation of inflammation removing.

SUMMARY OF THE INVENTION

The present invention relates to a multi— micro pore sheet for

i s recovering human body characterized by the composition of

biodegradable polymer and its low moisture ratio than l OOppm.

More Particularly, the present invention relates to a process of

preparing multi— micro pore sheet for recovering human body

20 characterized by the heat treatment of prepared biodegradable multi-

micro pore sheet under dry air or nitrogen atmosphere, and reiterating the process of nitrogen substitution and vacuum treatment after

sterilized with ethylene oxide or γ— ray. The biodegradable multi-micro

pore sheet of the present invention is prepared by forming one of the

followings in the forming frame of multi— micro pore sheet; (i) pile up

woven fabric, knitted fabric, chopped braid or non-woven fabric made

of biogradable staples or filaments more than 1 layers, (ii) membrane of

biogradable polymer (iii) powder of biogradable polymer.

BRIEF DESCRIPTION OF THE DRAWING

Figure 1 is magnified drawing of multi— micro pore sheet for

recovering human body of the present invention composed of

biodegradable nonwoven fabric.

Figure 2 is magnified drawing of multi— micro pore sheet for

recovering human body of the present invention prepared by forming a

powder of biogradable resin.

Figure 3 is magnified picture of multi— micro pore sheet for

recovering human body of the present invention prepared by dissolving

hydrophilic salt of the sheet which has been produced by forming

powder of biogradable resin and hydrophilic salt. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Multi-micro pore sheet of the present invention is prepared by

the following 2 steps that:

5 — Produce woven or knitted fabric by weaving or knitting biogradable

filament, and

— Pile up the said woven fabric or knitted fabric more than 1 layers.

Either mono filament or multi filament is applicable for the said

ι o biogradable filament. Mono filament is- good for the multi-micro pore

sheet which requires strong prop, and multi filament is good for the

multi— micro pore sheet which requires flexibility. It is favorable to cut

the prepared woven or knitted fabric with laser cutter. Warp and weft of

the chopped section should not be untied. During the heat treatment on

15 the said woven or knitted fabric under dry air or nitrogen atmosphere, it

is also favorable to give some tensile force for better supporting.

In the mean time, the multi— micro pore sheet of the present

invention is prepared by piling up more than 1 layers of non— woven

20 fabric which is made of biodegradable filament or staple. In general,

non-woven fabric is made by melt spun bonding, melt blowing, solution spinning and needle punching.

Among those methods, melt spun bonding is briefly explained

hereunder. Provide rectangular shaped spin pack having several nozzles

arrayed in several row with spinning dope of biodegradable polymer,

and spin out the said dope. The filament spun out through nozzle cools

down when it passes through freezing barrel, and the filament draws

when it passes through exhausting area. Not like the production of

filament for usual textile, the direction of air spinning is same with the

traveling direction of filament. By passing through the exhaust pipe, the

speed of filament gets as fast as 1 ,000—4,000 m/min. and then the

filaments draw each other. At the time the gap of exhaust pipe get

broadened, the air will tumble down, and the traveling speed of filament

slow down. At this moment, the filaments get entangled each other and

form web. Prepare non-woven fabric by piling up 2 or more than 2

layers of the said web on transportation belt. Prepare the desired thick

of non— woven fabric by melting compress the transported web using

calendar roller.

Meanwhile, multi— micro pore sheet of the present invention may

also be prepared by piling up the chopped braid which has been produced by braiding the biodegradable filaments with Braider

In the mean time, the membrane of biodegradable polymer

produced by the following process can be applied for preparing the

multi— micro pore sheet of the present invention.

(i) Prepare circular knitted fabric by knitting the filaments made of

biodegradable polymer with circular knitting machine,

(ii) Melt the biodegradable resin in volatile solvent and prepare the

coating solution,

(iii) After repeating several times of coating the said coating solution

wherein biodegradable was melted, wash and dry up several times

as the quantity of solution on the said circular knitted fabric remains

less than lOppm, and

(iv) Use laser for the preparation of the membrane of biodegradable

polymer by forming holes having same size and interval.

In case, filament of polyglycol acid has been used during the

preparation of circular knitted fabric, It is favorable to prepare coating

solution by melting the poly( l -lactic acid) in such solvent as

methylenecloride or ethanol. In the mean time, multi-micro pore sheet of the present

invention may be prepared by forming the powder of biodegradable

polymer in the forming frame of multi— micro pore sheet. As an instance,

prepare powder of 10—500 μm, more favorably 20— 250 μm sized

5 biodegradable polymer by shattering high molecule of poly ( 1 — lactic

acid) having more than 100,000 average molecular weight with mesh. If

the size of powder is less than 10 μ , the growth of fibrous blood vessel

tissue gets lowered. If the size of powder is over than 500 μm, i is not

possible for multi— micro pore sheet to function as prop properly.

ι o Multi— micro pore sheet in such case could be broken during

transportation or operation.

Equally spray the powder of poly ( 1 — lactic acid), the said

biodegradable polymer, in multi— micro pore sheet production frame

is having certain thickness, width, and length, and prepare the multi— micro

pore sheet by forming for 3 minutes under the pressure of 0.5kg/cn at

125 ^°C . The thickness, width and length of the multi-micro pore sheet

are not specifically restricted, but the favorable requirements are

0.4—4.5 mm thick, 20 mm wide and 260 mm long. In the mean time, multi-micro pore sheet of the present

invention also be prepared by the following process:

(i) Form the sheet with (a) powder of biodegradable polymer and (b)

the mixture of hydrophilic salt and/or gelatine, and

(ii) Melt the hydrophilic salt and/or gelatine remained in the said sheet

by distilled water treatment.

In forming the said sheet, 2 methods are possible that:

■ Put the compound of (a) powder of biodegradable polymer and (b)

the mixture of hydrophilic salt and/or gelatine in the sheet

production forming frame, or

■ Put only the powder of biodegradable polymer in the forming frame

for primary forming, and pile up the primarily formed sheet and

hydrophilic salt and/or gelatine in the separate forming frame for

secondary forming.

If sheet is prepared by the above second method, it is favorable

to set the temperature of primary forming lower than melting point of

biodegradable polymer and to set the temperature of secondary forming

higher by 5—30 °C than melting point of biogradable polymer. Besides, it

is favorable to control the pressures of primary and secondary forming at 0.005~0.05kg/cπ for first 2-5 minutes and 2~8kg/cnf for last 5-30

seconds before the completion for effective permeation of hydrophilic

salt and/or gelatine to the inside of organic soluble sheet.

5 In case, the powder of polyglycol acid is used, it is favorable to

set the temperatures at 120—200 °C for primary forming and at

230—250 °C for secondary forming. If the powder of poly( l -lactic acid)

is used, it is favorable to set the temperatures at 110—150 ^°C for

primary forming and at 180—210 ^°C for secondary forming. Therefore, it

ιo would be better to control the forming temperature depends on the heat

properties of applied organic soluble high molecule. In the present

invention, salt, magnesiumcloride, calciumcloride or kaliumcloride is

used for hydrophilic salt. It is favorable to control the average diameter

of hydrophilic salt between 20—500 μm since the average diameter

i s effects directly to the average diameter of micro pore formed in multi-

micro pore sheet.

It is more desirable to use supersonic wave with distilled water

when it comes to melt the remainder hydrophilic salt and/or gelatine in

0 the formed sheet. Coming out the hydrophilic salt and/or gelatine from

the sheet, like Figure 3, several micro pore are formed on the sheet. It is desirable to control the size of hydrophilic salt as the average

diameter of micro pore maintains between 20—500 μm.

After preparation of the biodegradable multi— micro port sheet

5 by the said various methods, control the required intensity by cutting

certain length, heat treatment under dry air or nitrogen atmosphere.

Prepare multi-micro pore sheet for recovering human body by the

following process:

ι o • Put the heat treated multi-micro pore sheet in aluminum foil pack,

and seal the outside with disinfection pack,

• Sterilization treatment with Ethylene Oxide or 7 - ray,

• Control the moisture ratio of final product less than l OOppm by the

reiteration process of nitrogen substitution and vacuum utilizing

15 disinfector or vacuum oven for the purpose of long term storage,

and

• Seal in aluminum foil.

Biodegradable polymer of the present invention is poly

₂₀ glycloride, poly lactide, poly glycol acid, poly lactic acid, poly dioxide,

poly trimethylene carbonate, poly caprolacton, copolymer or blend of the above polymer. Tin octoate is mostly used as the catalyzer of

biodegradable polymer. Alcoholic class is added as the controller of

molecular weight. In case, poly(p— dioxide) is used for obtaining high

molecular weight, copolymerization is preferred to melting

polymerization. It is required to maintain the average molecular weight

over than 120,000 in this situation ,or more preferably over than

200,000. It is desirable to set the temperature of heat treatment

between 70—90 ^°C . Since the solvent for poly glycol acid is very limited,

it is favorable to use melting viscosity as criterion. For instance, over

than 300 poise of shear rate at 240 °C , 10/sec would be adequate.

Since the multi— micro pore sheet for recovering human body of

the present invention is composed of biodegradable polymer, it not only

functions as prop during the growth of fibrous blood vessel for the

complete cure of fracture, but has no necessary for another removing

operation. Besides, the multi— micro pore sheet for recovering human

body of the present invention were used in roll shape by winding, it is

easy to use by cutting desired size or by folding several plies. Since no

solvent is applied during the preparing process of the multi— micro pore

sheet for recovering human body of the present invention, it is possible

to control the preparing process, to shorten the preparing time, to improve transportation stability.

Though it is not specifically restricted in width and thickness of

the multi— micro pore sheet for recovering human body of the present

invention, it is desirable to be 20— 60mm in width and 0.3—5.0mm in

thickness. Multi-micro pore sheet for recovering human body of the

present invention is used as prop for the operations such as recovering

facial cranium fracture, recovering eye sockets fracture, recovering

concha fracture, auxiliary nasal cavity, and recovering scaffold tissue.

More concretely, the present invention shall be examined

through examples hereunder. The present invention, however dose not

restrict only to following examples.

Example 1

After shattering poly( l -lactic acid) having 379,000 of average

molecular weight, prepare 100— 200 μm sized powder by utilizing mesh.

Equally put the said powder to the forming frame for multi— micro pore

sheet at 0.85mm thick, 20mm wide, 260mm long, then cover the upper

part of forming frame. Do form for 3 minutes at 125 ^°C and 0.5kg/cm\ then cut the formed multi— micro pore sheet per 25mm unit after cool

down. The cavity size of prepared multi-micro pore sheet is 50—150 μm-

After heat treatment of 3 hours under nitrogen atmosphere at 90 ^°C , put

the prepared multi— micro pore sheet in the aluminum foil pack. Seal the

outside with disinfection pack, and sterilization treatment with ethylene

oxide. Control the moisture ratio of the multi-micro pore sheet at

50ppm by the 5 times reiteration process of nitrogen substitution and

vacuum process at 80 °C . Seal the said aluminum foil to prepare multi-

micro pore sheet for recovering human body.

Example 2

Under tin octoate catalyzer, prepare lump of poly(p— ioxide)

having 320,000 average molecular weight by polymerizing dioxide

monomer for 24 hours at 100 °C . Prepare 80— 100 μm sized powder with

mesh after shattering. Equally put the said powder to the forming frame

for multi— micro pore sheet at 1.5mm thick, 20mm wide, 260mm long,

then cover the upper part of forming frame. Do form for 2 minutes at

125 "C and 0.3kg/cm', then cut the formed multi-micro pore sheet by

25mm unit after cool down. The cavity size of prepared multi-micro

pore sheet is 80—180 μm- After heat treatment of 4 hours under nitrogen atmosphere at 70 ^°C , put the prepared multi— micro pore sheet in the

aluminum foil pack. Seal the outside with disinfection pack, and

sterilization treatment with ethylene oxide. Control the moisture ratio of

the multi— micro pore sheet at 30ppm by the 5 times reiteration process

of nitrogen substitution and vacuum process at 70 °C . Seal the said

aluminum foil to prepare multi— micro pore sheet for recovering human

body.

Example 3

Under tin octoate catalyzer, prepare 1mm diameter poly(glycol

acid) pellet having 40,000 poise melting viscosity under 10/sec of shear

rate and 24 ^°C , by polymerizing glycol acid monomer for 2 hours at

235 ^°C . After melt the said pellet by the extruder, spin the melted pellet

through nozzle having 0.35mm diameter and 1.3mm length. Prepare

drawn yarn having 96denier/48filament through 3 steps of drawing. The

properties of drawn yarn is 8.6g/denier in its strength, 28% in its

shrinkage. Weave the said drawn yarn to prepare plain fabric having

30cm in its width from narrow weaver. Cut the fabric at 20mm wide and

260mm long by laser cutter. Allowing 30g of tensile force, heat

treatment for 3 hours at 110 "C under nitrogen atmosphere. After scrolling the heat treated fabric on roller, put the scrolled multi— micro

pore sheet in the aluminum foil pack. Seal the outside with disinfection

pack, and sterilization treatment with ethylene oxide. Control the

moisture ratio of the multi-micro pore sheet at 20ppm by the 7 times

reiteration process of nitrogen substitution and vacuum process at

100 ^°C . Seal the said aluminum foil to prepare multi— micro pore sheet

for recovering human body.

Example 4

Prepare braided tube by braiding 96filament/1000denier poly( l —

lactic acid) with 32 spindle braider. Cut the both ends of the said tube

with laser cutter, and prepare braided multi— micro pore sheet having

1.5mm in its thickness, 20mm in its width and 30— 70 μm in its cavity

5 size. Except the lOOg of tensile force, perform heat treatment in the

same conditions as example 1. Prepare multi-micro pore sheet for

recovering human body having 50ppm of moisture ratio through the

same process as example 1 thereafter.

o Example 5 Prepare plain fabric by weaving poly( l -lactic acid) mono

filament having 0.42mm in its diameter, 7.5kg in its strength force, and

45% in its shrinkage. Cut the said fabric with laser cutter having 20mm

5 in its width and 20—60 μm in its cavity size. Except the 45g of tensile

force, perform heat treatment in the same conditions as example 1.

Prepare multi— micro pore sheet for recovering human body having

50ppm of moisture ratio through the same process as example 1

thereafter.

1 0

Example 6

Prepare knitted fabric by knitting poly glycol acid filament having

8.0g/denier of strength force, 32% of shrinkage, 75denier/36filament

i5 with circular knitting machine. In the mean time, prepare coating

solution by putting, mixing, and melting 50 weight part of poly( l -lactic

acid) having 379,000 average molecular weight in the mixture of

methylene cloride and ethanol. Prepare 0.85mm thick sheet(knitted

fabric:coating solution weight part=50:50) by repeating 3 times of

₂o coating the said coating solution in the said knitted fabric made of the

filament of poly glycol acid. Wash and dry up the prepared sheet 2 times as the quantity of solution remains less than lOppm. Then,

prepare multi— micro pore sheet having 200 μ diameter cavities in 4mm

equal interval by utilizing laser. After cut the prepared multi— micro

pore sheet at 20mm wide, 260mm long, lOg tensile force heat treatment

will be followed under nitrogen atmosphere. Prepare multi— micro pore

sheet for recovering human body having 50ppm of moisture ratio

through the same process as example 1 thereafter.

Example 7

Extrude poly ( 1 — lactic acid) spinning dope having 280,000

average molecular weight through rectangular spinning mesh having 480

holes of 1.8mm in its array. Cool down the extruded filament by passing

through the cooling device. Draw the said filament by passing through

exhausting area in the same direction with air. After that, form web by

tumbling down. Prepare non woven fabric by melting pressure with

Kalendar Roller after piling the said web by 2 plies on conveyor belt. In

this process, control the spinning speed of filament at 2,000m/min.,

winding speed of filament at lOOm/min., calendar roller temperature at

115 °C , calendar roller pressure at lkg/cn . Cut the prepared non woven

fabric by 20mm wide and 260mm long. And then, 15g tensile force heat treatment will be followed under nitrogen atmosphere. Prepare multi-

micro pore sheet for recovering human body having 50 μm and 0.84mm

thick cavity through the same process(disinfection, nitrpgen substitution,

vacuum treatment and sealing) as example 1 thereafter.

Example 8

After shattering poly glycol acid pellet having 40,000 Poise

melting viscosity under 10/sec. of shear rate and 240 ^°C , prepare 80 μm

average diameter sized powder by utilizing shatter. After equally put

the said powder to the forming frame, Do primary forming for 3 minutes

at 170 ^°C and 0.009kg/cπ pressure. Prepare the primary sheet whereat

some poly glycol acid were melted and attached, by elevating the

pressure to 4.5 kg/cn for 10 seconds prior to the completion of primary

forming. Distribute salt powder having 140 μm of average diameter on

the bottom of separate forming frame, and put the prepared primary

sheet thereon. And then distribute salt powder having 140 μm of average

diameter again just like sandwich. After covering the upper part of

forming frame, perform secondary forming for 2 minutes at 230 °C and

0.009kg/cn pressure. Prepare the secondary sheet by elevating the

pressure to 5kg/cnf for 10 seconds prior to the completion of secondary forming. Remove the forming frame, and cool down in the normal

temperature. Take out the secondary sheet containing salt powder, and

completely remove the salt under 70 °C distilled water and supersonic

wave in order to prepare multi— micro pore sheet. After heat treatment

of 4 hours under nitrogen atmosphere at 70 ^°C , put the prepared multi-

micro pore sheet in the aluminum foil pack. Seal the outside with

disinfection pack, and sterilization treatment with ethylene oxide.

Control the moisture ratio of the multi-micro pore sheet at 30ppm by

the 5 times reiteration process of nitrogen substitution and vacuum

process at 70 °C . Seal the said aluminum foil to prepare multi— micro

pore sheet for recovering human body. The properties of finally

prepared sheet are 0.85mm thick, 25mm long, 23mm wide and 125 μm

average diameter of micro pore.

Example 9 — Example 15

Except the changes of preparing conditions as shown Table 1 ,

prepare multi— micro pore sheet by the same process as Example 8.

Table 2 shows the properties of the respective prepared sheets.

<Table 1 > Preparing Conditions

<Table 2 > Thickness, length, width and micro pore average diameter

of prepared sheet

Claims

WHAT IS CLAIMED IS:

1 . A multiΓÇö micro pore sheet for recovering human body characterized

by the composition of biodegradable polymer and its low moisture

ratio than lOOppm.

2. A multiΓÇö micro pore sheet for recovering human body of claim 1 ,

wherein the width of sheet is 20ΓÇö 60mm, and the thickness of sheet

is 0.3ΓÇö 5.0mm.

3. A multiΓÇö micro pore sheet for recovering human body of claim 1 ,

wherein the biodegradable polymer is poly glycloride, poly lactide,

poly glycol acid, poly lactic acid, poly dioxide, poly trimethylene

carbonate, poly caprolacton, copolymer or blend of the above

5 polymer.

4. A multiΓÇö micro pore sheet for recovering human body of claim 1,

wherein the multiΓÇö micro pore sheet is piled up of woven fabric,

knitted fabric, braid or nonΓÇö woven fabric made of biodegradable

o polymer staples or filaments more than 1 layers,

5. A multiΓÇö micro pore sheet for recovering human body of claim 1 ,

wherein the multiΓÇö micro pore sheet is membrane of biodegradable

polymer or powder of biodegradable polymer.

6. A process for preparing a multi-micro pore sheet for recovering

human body characterized by preparing of biodegradable multi-

micro pore sheet wherewith the powder, membrane, woven fabric,

knitted fabric, braid, or non woven fabric composed of biodegradable

polymer, by the heat treatment of prepared biodegradable multi-

micro pore sheet under dry air or nitrogen atmosphere, and

reiterating the process of nitrogen substitution and vacuum

treatment after sterilized with ethylene oxide or ╬│ΓÇö ray.

7. A process for preparing a multiΓÇö micro pore sheet for recovering

human body of claim 6, wherein the biodegradable polymer is poly

glycloride, poly lactide, poly glycol acid, poly lactic acid, poly

dioxide, poly trimethylene carbonate, poly caprolacton, copolymer or

blend of the above polymer.

8. A process for preparing a multi-micro pore sheet for recovering

human body of claim 6, wherein the the multiΓÇö micro pore sheet is

prepared by the following process:

(i) Form the sheet with (a) powder of biodegradable polymer and

(b) the mixture of hydrophilic salt and/or gelatine, and

(ii) Melt the hydrophilic salt and/or gelatine remained in the said

sheet with the distilled water treatment.

9. A process for preparing a multi-micro pore sheet for recovering

o human body of claim 8, wherein the use of distilled water for melting

the remainder hydrophilic salt and/or gelatine in the formed sheet

under supersonic wave.

10. A process for preparing a multiΓÇö micro pore sheet for recovering

5 human body of claim 8, wherein the hydrophilic salt is salt,

magnesiumcloride, calciumcloride or kaliumcloride.

1 1. A process for preparing a multiΓÇö micro pore sheet for recovering

human body of claim 8, wherein the average diameter of micro pore

o is 20ΓÇö500 ╬╝m, the thickness of micro pore is 0.3ΓÇö 5.0mm, and the

moisture ratio is less than lOOppm.