DE102012000103A1 - Orthopedic liner for rolling on skin of amputation stump of patient, has layer made of chemical vapor deposited poly p-xylylene and exhibiting property of non-adherence to skin, and another layer made of polymeric cushion material - Google Patents

Abstract

The liner has a first layer (1) for contacting a skin, and a second layer (2) exhibiting a damping function. A third layer (3) is made of elastic knitted fabric, and the first layer is made of Parylene (RTM: chemical vapor deposited poly(p-xylylene)) and exhibits a property of non-adherence to the skin, where average thickness of the first layer is 0.5-5 micrometer. The second layer is made of a polymeric cushion material i.e. polymer gel. The elastic knitted fabric comprises a mixture of polyester, cotton and spandex, where thickness of the elastic knitted fabric is 0.8-2.5 mm.

Description

The invention relates to an orthopedic liner.

Orthopedic liners are known from the prior art, wherein the known liners basically consist of two layers. From the EP 762857 An orthopedic liner is known comprising a cushioning material and a fabric having an open end for insertion of the stump and a closed end opposite the open end, the fabric being coated on at least its inside with a tight polymeric cushioning material covering the skin of the body Amputation stump contacts when worn by a user to minimize or eliminate air pockets.

Such liners are rotated to be tightened to their left side and preferably held with the closed end at the amputation site to then roll over the amputation stump. It is the nature of these liners that the polymeric cushion layer on its inside will have contact with the skin and have an almost self-adhesive property due to the physico-chemical properties of the polymeric upholstery fabric. This self-adhesive property leads to significant disadvantages in the daily handling of such a liner.

It is very important for the amputee, before putting on these liners, to ensure that the self-adhesive padding layer does not come into contact with dust or other particles as they adhere to the padding layer and cause unpleasant irritations on the skin. Especially during rotation on the left side of the liner, there is the danger that the completely outwardly turned side of the cushion layer may fall to the ground and the dust or dirt particles located there adhere to the liner. In such a situation, the patient must clean the liner prior to mounting on the amputation stump, for example, wash it and then dry it before he can reuse it.

But even if there is no danger that the liner falls on the floor in the everted state, skin flakes and hair, which detach themselves from the body during wear and have contact with the polymer layer, adhere to the polymeric cushion layer.

These contaminants are unhygienic and are also perceived by the wearer to be unhygienic, so that usually after each wear the wearer has the need to wash out the liners. Depending on the activity of the wearer, the wearer may change liners several times a day. For some sports, such as swimming, there are liners with other physical properties or docking facilities, so changing the liner may be necessary.

The object of the present invention is therefore to provide a liner which does not have the disadvantage described above.

The orthopedic liner according to the invention consists of three layers: a first layer intended for skin contact, a second layer having a cushioning function and a third layer consisting of an elastic knitted fabric, the first layer consisting of parylene and the Property does not adhere to the skin and the second layer is made of a polymeric cushioning material.

Advantageously, the first layer of the polymer parylene, The preferred thickness of the first layer is between 0.1 .mu.m and 10 .mu.m. Particularly preferred is an average thickness between 0.5 microns and 5 microns.

To produce the liner, the knit fabric is first produced, for example on a circular knitting machine, which will eventually form the third layer. The preferred material for making the knitted fabric is a blend of polyester, cotton and elastane having a basis weight of about 150-350 g / m ² . In a preferred embodiment of the present invention, the yarn is about 96% polyamide and about 4% spandex. The thickness of the yarn is between 0.1 to 0.5 mm, the thickness of the resulting knitted fabric is between 0.8 to 2.5 mm.

The elasticity required for the mechanical properties is achieved on the one hand by the yarn having a modulus of elasticity of 5,000-6,000 N / mm ² and by the type of stitch formation. For the invention advantageous jersey has proven, as it is known for example in sportswear. However, other manufacturing methods for the knitwear are possible, such as knitting.

After producing the knitwear as a third layer, it is turned to "left" and provided with the second layer in the production process, either in a dip strip or by injection molding. Such a dipping method is also known from the prior art. The thickness of the second layer can be selected depending on the application and comfort requirements. The average thickness of the second layer is 2 to 10 mm.

After preparation of the second layer, this must be cooled. For this purpose, a cone-shaped stand, on which the liner "left" turned up to dry is ideal. According to the invention, the second layer is coated with the first layer. For this purpose, the polymer Parylene is used according to the invention.

• 1. Verdampfen des festen Dimers. Dieses wird im Vakuum auf ca. 150–220 Grad Celsius erhitzt und in Gas umgewandelt.
• 2. Das Gas wird pyrolysiert, d. h. thermo-chemisch in seine organische Verbindungen aufgespaltet, um das Dimer in seine monomere Form zu spalten.
• 3. Das monomere Gas wird in der Abscheidungskammer bei Raumtemperatur als transparenter Polymerfilm abgeschieden.

The coating of the second layer takes place at the molecular level and consists essentially of three steps.

• 1. Evaporation of the solid dimer. This is heated in vacuum to about 150-220 degrees Celsius and converted into gas.
• 2. The gas is pyrolyzed, ie, thermo-chemically broken down into its organic compounds to cleave the dimer into its monomeric form.
• 3. The monomer gas is deposited in the deposition chamber at room temperature as a transparent polymer film.

• • Parylene C = sehr gute elektrische und physikalische Eigenschaften < 140°C
• • Parylene N = größte Beschichtungs-Penetration < 90°C
• • Parylene D = hohe Barriereschicht und Temperaturschutz < 180°C
• • Parylene F = gute elektrische Eigenschaften und Temperaturschutz > 250°C

Altogether one differentiates 4 different Parylene Dimer:

• • Parylene C = very good electrical and physical properties <140 ° C
• • Parylene N = largest coating penetration <90 ° C
• • Parylene D = high barrier layer and temperature protection <180 ° C
• • Parylene F = good electrical properties and temperature protection> 250 ° C

The following structural formulas represent the structure of the parylene:

Conformal parylene coatings for the first layer are very thin, pore-free polymer coatings, which according to the invention are between 0.1 μm and 10 μm. Due to the smooth nature of the parylene layer particles do not adhere to it. Only statically charged particles adhere quickly and can be removed by shaking or brushing.

Parylene is an inert, hydrophobic, optically transparent, biocompatible, polymeric coating material.

The coating is carried out without temperature load of the liners according to the invention at room temperature in vacuo. The first layer according to the invention, with uniform layer formation, temperature resistant up to 220 degrees Celsius, mechanically stable from -200 ° C to + 150 ° C and abrasion resistant.

• 1. eine verbesserte Reinigung und damit einhergehend weniger Hautprobleme
• 2. ein verbessertes Handling durch Anschmutzungsunempfindlichkeit
• 3. eine verlängerte Lebensdauer der Polsterschicht
• 4. verbesserte Hautverträglichkeit des Liners durch Schutz vor dem Gelmaterial

The orthopedic liner according to the invention achieves the following advantages over the prior art:

• 1. an improved cleaning and concomitantly less skin problems
• 2. an improved handling by soiling insensitivity
• 3. an extended life of the cushion layer
• 4. Improved skin compatibility of the liner by protection against the gel material

In conventional gel liners, the disadvantage is the limited ability to clean the padding material, which is in direct skin contact. Due to this intense contact between the thermoplastic elastomer gel and the skin of the amputation stump the gel material is loaded with sweat, dander, etc., which penetrate over time into the gel and with conventional cleaning techniques such. As water and soap, disinfecting the surface with alcohol, etc. are very difficult to remove again.

Treatment of the liner in the autoclave would destroy the liner because the related temperature would cause the gel to melt and thus destroy the liner.

• • hydrophobe Eigenschaft der Beschichtung: der erfindungsgemäße Liner ist einfach zu reinigen und trocknet schnell
• • Bakterienbefall blockiert durch porenfreie Beschichtung: fast alle unangenehmen Gerüche werden eliminiert
• • Reduzierung von Hautirritationen durch chemie- und pilzresistente Beschichtung

A coating according to the invention of the second layer with parylenes has the following advantageous effects on the liners according to the invention:

• Hydrophobic property of the coating: the inventive liner is easy to clean and dries quickly
• • Bacterial attack blocked by non-porous coating: almost all unpleasant odors are eliminated
• • Reduction of skin irritation through chemical and fungus resistant coating

The hydrophobic surface coating prevents "penetration" of the sweat / body fluids into the gel material. As a result, the liner is easier to clean because the dirt is only on the surface and does not migrate into the gel material.

The "stickiness" of the second layer known from the prior art is avoided by the coating in the case of the liner according to the invention. The unwanted stickiness is avoided in the prior art by applying a talcum powder. A treatment with talcum powder is completely eliminated in the inventive liner.

The adhesion of dirt and / or foreign particles caused by the stickiness in the conventional liners means that they can no longer be attracted to patients. The contamination may, for example, be caused by the fact that the often geriatric user slides the liner out of his hand when he puts it on and falls to the floor. For example, carpet fuzz, dust, etc. are held by the sticky surface and pollute them.

Another danger of contamination is that the amputee, when he drops his liner, for example, on the beach for swimming, must carefully protect it from sand and earth, as this otherwise adheres to the conventional liner and is difficult to remove.

The liner described in this invention combines the benefits of easier cleaning as known from silicone liners with the improved cushioning capabilities of a thermoplastic elastomer liner.

If the amputee uses the soiled liner because of the lack of cleanability, it can lead to pressure and chafing on the usually very fragile amputation stump, which can subsequently inflame and severely hinder the amputee.

Another advantage of the liner according to the invention lies in the longer life of the cushioning material when it is coated with the parylene according to the invention.

The increased life results from the increased abrasion resistance as well as the fact that no body fluids migrate into the polymer cushion layer and this does not pick up and absorb unpleasant body odors. Furthermore, the life is increased by the fact that no or less body fluids such as urine migrate into the padding material and lead to its decomposition.

In a particularly preferred embodiment of the present invention, the coating of the second layer with Parylene N is made.

The resulting protective layer gives the product improved cleaning and a low tendency to stain. The skin of the amputation stump is isolated from the gel material by a surface protection layer that is both highly biocompatible and non-abrasive, giving the product a longer life. The used Parylene N reach in the coating of the thermoplastic elastomers the largest coating penetration and thus produce an effective connection to the thermoplastic, which is not destroyed even at higher loads.

The composition of the gel consists of a mixture of 10-45% of one or a mixture of different styrene block copolymers (SEEPS, SEBS, SBS, SEPS, MBS) with a 55-85% process oil, one or more antioxidants, admixtures of polypropylenes or Polyethylene and silicone oil.

The thickness of the polymer gel is preferably between 2 and 10 mm thick. The hardness of the polymer gel is between 10 and 65 Shore 0.

The thermal properties of the parylene are summarized in the following table: Typical thermal properties N C D F Melting point (° C) 410 290 360 > 460 Linear expansion coefficient (ppm / ° C) 69 35 38 36 Thermal conductivity, @ 25 ° C Watts / meter, Kelvin 0,120 0.082 n / A 0.096 Continuous temperature * (° C) 90 125 160 350 Temporary peak temperature * (° C) 120 200 300 450

The physical and mechanical properties of the parylene are summarized in the table below. Typical physical and mechanical properties N C D F Tensile strength, psi 6500 10,000 11,000 7500 Tensile strength, MPa 45 69 76 52 Yield point, psi 6300 8000 9000 5000 Yield point, MPa 43 55 62 34 Tensile modulus, psi 350000 400000 380000 370000 Tensile modulus, MPa 2400 3200 2800 2500 Elongation at break,% 250 200 200 200 Flow elongation,% 2.5 2.9 3.0 2.0 Density, g / cm ³ 1,110 1,289 1,418 1.32 Coefficient of friction: static 0.25 0.29 0.33 0.14 Dynamic 0.25 0.29 0.31 0.13 Water intake:% (24 h) 0.01 0.06 <0.1 <0.009 Refractive index, n _D ²³ 1,661 1.639 1,669 1.559

The typical electrical properties of the parylenes are summarized in the table below. Typical electrical properties N C D F Short term throughput (volts / mil at 1 mil) 7000 5800 5500 5500 Volume Resistance, 23 ° C, 50% RH (Ohm-cm) 1 × 10 ¹⁷ 6 × 10 ¹⁶ 2 × 10 ¹⁶ 2 × 10 ¹⁷ Surface resistance, 23 ° C, 50% RH (ohms) 10 ¹⁵ 10 ¹⁵ 5 × 10 ¹⁶ 5 × 10 ¹⁵ Dielectric constant: 60 Hz 2.65 3.15 2.84 2.25 1,000 Hz 2.65 3.10 2.82 2.1 1,000,000 Hz 2.65 2.95 2.80 2.16 Dielectric loss factor: 60 Hz 0.0002 0,020 0,004 0.0002 1,000 Hz 0,002 0.019 0,003 0.0020 1,000,000 Hz 0.0006 0,013 0,002 0.0010

The typical protective properties of the parylene are summarized in the table below. Typical protection properties N C D F Gas permeability (23 ° C) (α × mm) / (m ² × 24 hr × atm) nitrogen 7.7 0.37 1.77 4.85 oxygen 11.81 2.8 12.6 23.5 carbon dioxide 84.25 3.03 5.12 95.6 hydrogen sulfide 313.0 5.12 0.57 n / A sulfur dioxide 0.74 4.33 1.87 n / A chlorine 29.13 0.14 0.22 n / A hydrogen 212.6 43.31 94.49 n / A Moisture permeability, (g × mm) / (m ² × 24 hr), 37 °, 90% RH 0.59 0.06 0.1 0.23

The average persistence of the parylene is summarized in the table below. Resistance to chemicals (acids, alkalis, solvents) Diving conditions N C D F Hydrochloric acid 10% 75 ° C / 120 min +0.08 -0.28 +0.21 n / A Sulfuric acid 10% 75 ° C / 120 min +0.07 -0.28 +0.14 n / A Nitric acid 10% 75 ° C / 120 min +0.15 -0.28 +0.21 n / A Hydrofluoric acid 10% 50 ° / 120 min +0.37 +0.09, +0.27 n / A NaOH solution 10% 75 ° C / 120 min +0.15 -0.28 +0.14 n / A NH4OH solution 10% 75 ° C / 120 min +0.15 -0.38 +0.22 n / A Hydrogen peroxide (H2O2) 50 ° C / 120 min 0.00 0.00 +0.17 n / A n-octane 75 ° C / 120 min +0.29 +0.28 +0.39 B n / A Toluen coal tar oil 75 ° C / 120 min +0.30 +1.32 +3.69 B n / A Monochlorobenzine 75 ° C / 120 min +0.37 +1.04 +3.47 B n / A pyridine 75 ° C / 120 min +0.29 +0.28 +3.41 n / A 2-propanol (PA) 50 ° C / 120 min +0.07 0.00 0.0 n / A acetone 50 ° C / 120 min +0.15 -0.09 +2.38 n / A

A preferred embodiment of the orthopedic liner according to the invention will be described with reference to the figure. The figure shows a liner according to the invention with a first layer 1 , a second layer 2 and a third layer 3 , All layers are interconnected in such a way that shear forces can easily be transferred between the layers. layer 1 has as the only layer in direct contact with the skin of the wearer of the liner according to the invention. Thus, the disadvantages described are reliably avoided.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 762857 [0002]

Claims (5)

Orthopedic liner consisting of three layers; • a first layer intended for skin contact; A second layer having a dampening function; A third layer consisting of an elastic knitted fabric, wherein the first layer is parylene and has the property of not adhering to the skin and the second layer is made of a polymeric cushioning material. An orthopedic liner according to claim 1 wherein the first layer is Parylene N. An orthopedic liner according to claim 2, wherein the first layer is between 0.1 μm and 10 μm. An orthopedic liner according to any one of the preceding claims wherein the second layer is a polymer gel. Orthopedic liner according to one of the preceding claims, wherein the third layer consists of a textile knitwear.

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