EP2867107A1

EP2867107A1 - Improved support structure for the human body

Info

Publication number: EP2867107A1
Application number: EP13765772.2A
Authority: EP
Inventors: Giuseppe Bigolin
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-06-27
Filing date: 2013-06-27
Publication date: 2015-05-06
Also published as: CH706685A2; WO2014002047A1

Abstract

A human body support structure comprises a shell (2) with a pad (4) thereon, the latter being in turn covered by a cover (7). The pad (4) and/or the cover (7) are made from a formulation comprising at least one fossil-derived polymeric material and at least one renewable source-derived material, and the materials in the formulation are selected such that the carbon footprint, as defined in accordance with the standard ISO 14067 in terms of amount of carbon dioxide equivalent (CO2e) per unit weight of the formulation is relatively low and the percent radiocarbon-14 (pMC), as defined according to the standard ASTM D6866 per unit weight of the formulation is relatively high. The formulation for forming the lower layer (5) of the pad (4) comprises a foamed polymeric preparation comprising a polyol phase, an isocyanate phase, an additive phase, and a plasticizer phase, wherein the additive phase comprises fossil-derived and renewable source-derived additives, the later comprising additives selected from the group comprising hydrogenated castor oil-derived plasticizers, crosslinking agents, catalysts, foaming agents, and wherein said plasticizers are derived from hydrogenated castor oil.

Description

IMPROVED SUPPORT STRUCTURE FOR THE HUMAN BODY

Technical Field

The present invention generally finds application in the field of human body support devices, and particularly relates to an improved and eco-friendly support structure.

Background art

Human body-support devices, such as saddles for bicycles or other pedal- powered machines, e.g. exercise bicycles and spinning bikes, but also seats and armchairs of machines in general, generally have a structure composed of at least one shell, designed to be fixed to the frame of the machine, a pad overlying the shell and a cover, designed to cover the pad and to contact the user body.

Technical problem

Patent application CH-A-71 6/12 by the Applicant hereof, discloses a human body support structure, such as a saddle or a seat for a vehicle or a similar machine, which basically comprises a shell, a pad overlying the shell and a cover for covering the pad. The pad and/or the cover are made from a formulation comprising at least one fossil-derived polymer material and at least one renewable source-derived material.

The materials in this formulation are selected such that the carbon footprint, as defined in accordance with the standard ISO 14067 in terms of amount of carbon dioxide equivalent per unit weight of the formulation is relatively low and the percent radiocarbon-14, as defined according to the standard ASTM D6866 per unit weight of the formulation is relatively high.

Furthermore, the formulation for forming the lower layer of the pad comprises a foamed polymeric preparation comprising a polyol phase, an isocyanate phase, an additive phase, and a plasticizer phase.

Also, the additive phase comprises fossil source-derived and renewable source-derived additives, the latter comprising additives, wherein the renewable source derivatives include additives selected from the group comprising hydrogenated castor oil-derived plasticizers, crosslinking agents, catalysts, foaming agents. The components of prior art support structures as defined above, which are commercially available, are typically made from fossil-derived polymer materials and wherein, preferably, the plasticizers are derived from castor oil.

Mechanically speaking, the comfort of the saddle as a whole may be associated with its compliance or resilience. While the shell has the purpose of supporting the weight of the user and is made of a relatively rigid or semi-rigid plastic material, such as high-density polyethylene, polypropylene, polyethylene, polyamide, PVC and other similar resins, the pad and the cover have the purpose of adding comfort to the saddle. Since these components are placed one on top of the other, and hence connected "in series", their compliance, and the comfort resulting therefrom, is given by the sum of the reciprocals of the stiffnesses of the individual components of the saddle and the stiffness of the saddle depends on the stiffness of the individual components, on the modulus of elasticity of the base material, the thickness and the residual stress state. As a rule, the polymer materials are selected from those having a relatively low modulus of elasticity, i.e. a relatively low Shore hardness.

These "soft" materials are obtained by mixing various polymers in the liquid state, some of which act as plasticizers. A plasticizer agent is a compound made of molecules that are much smaller than the macromolecules of the polymer, such that they may more evenly fit in between the macromolecules during mixing. Furthermore, the plasticizer must be able to be thoroughly mixed with the polymer, such that it may be stably and homogeneously incorporated in its mass and would not tend to migrate to the surface of the plastic material with time (which is known as "exudation"). The plasticizer shall also have little or no volatility, i.e. a high boiling point, because its effect would vanish when leaving the plastic material.

One drawback of these prior art formulations is that plasticizers containing pure castor oil, i.e. ricinoleic acid, may be particularly compact and characterized by a high hardness, e.g. of the order of 60 Shore C.

As a result, the pad may be less comfortable for users.

Disclosure of the invention

A general object of this invention is to overcome the above drawbacks, by providing a human body support structure that exhibits characteristics of eco- friendliness, reduced environmental impact, comfort, durability and cost- effectiveness.

A particular object is to provide an eco-friendly human body support structure that is made of material having a maximized renewable source-based content and, as a whole, a low carbon footprint, thereby assisting an eco-friendly development.

A further object is to provide a human body support structure having a minimized environmental impact, due to reduced employment synthetic materials derived from fossil sources.

Another object is to provide a human body support structure that has high softness and mechanical properties, namely low dynamic flex fatigue and high resilience.

These and other objects, as better explained hereafter, are fulfilled by a human body support structure as defined in the main claim.

Brief description of the drawings

Further features and advantages of the invention will be more apparent from the detailed description of a few preferred, non-exclusive embodiments of an human body support structure, e.g. a bicycle saddle, according to the invention, which is described as a non-limiting example with the help of the annexed drawings, in which:

FIG. 1 is a perspective view of a support structure, particularly a bicycle saddle, according to the invention;

FIG. 2 shows a partially broken-away view of the saddle structure of FIG. 1 , to highlight its main components;

FIG. 3 is a plan view of the saddle structure of FIG. 1 ;

FIG. 4 shows a view of the saddle structure of FIG. 3, as taken in a broken away view, along a longitudinal plane IV-IV;

FIG. 5 shows a view of the saddle structure of FIG. 3, as taken in a broken away view, along a transverse plane V-V.

Detailed description of exemplary embodiments

Referring now to the above figures, there is shown a human body support structure, particularly a saddle for bicycles, motorbikes or pedal-powered machines, such as an outdoor or indoor exercise bicycle.

Here, the saddle has a substantially elongate conventional shape, with a longitudinal symmetry axis, a tapered front portion designed for support of the scrotal or inguinal region of a user and a widened rear portion designed for support of the ischiadic region of the same user.

Alternatively, the support structure may also have a different shape, such as the shape of a seat, an armrest or a headrest, for a vehicle of any type, such as a motor vehicle, a boat, an aircraft, a work machine, without departure from the scope of the invention.

The saddle structure, generally designated by numeral 1 , comprises a support shell 2 which is adapted to be secured to a frame 3, the latter being designed to be fixed to a bicycle or a similar vehicle.

A pad, generally referenced 4, is formed on the shell 2, and comprises a lower layer 5 of a foamed polymer, with a layer 6 of a polymer gel lying thereon, which has at least a partial shape memory effect.

A cover 7 is formed on the pad 4, for covering the top surface of the pad and contact the body of the user.

The shell 2 is of conventional type and is made of a synthetic material, such as high-density polyethylene, polypropylene, polyethylene, polyamide, PVC and other similar polymer materials. Preferably, the shell 2 may be made of polypropylene.

Preferably, the upper layer 6 of the pad may be formed with a polyurethane or silicone gel.

Preferably, the coating 7 contains polymer materials such as PVC, thermoplastic polyurethane, polyurethane, Pebax® based on PA1 1 -Polyamide 1 1 .

Notwithstanding the conventional nature of the polypropylene shell, according to the invention the support is allowed to be eco-friendly by forming the pad 4 and the cover 7 with a formulation comprising at least one fossil-derived polymer material and at least one renewable source-derived material.

Particularly referring to the components of the pad 4, these generally consist of a foam or a gel which, as mentioned above, are generally of polyurethane nature, i.e. made of polymer chains consisting of urethane bonds.

Urethane polymers or PUs are obtained by reacting a diisocyanate (of aromatic or aliphatic type) and a polyol (polyethylene glycol or polyester) in the presence of catalysts and other additives to impart the desired characteristics to the material. If so-called "foaming" agents are added to polyol formulations, foamed polyurethanes may be obtained.

Foamed PUs may be found in the form of soft and flexible PUs, soft and integral or self-skinning PUs, rigid/structural PUs, rigid and compact PUs, and elastic and compact PUs.

Generally, two mechanisms are involved in the production of polyurethane foams: the first mechanism is the reaction of excess isocyanate with the hydroxyl groups of polyol, the second mechanism produces a blowing gas and generates the foam structure.

This latter process may be of chemical or physical nature: in the former case, the base synthesis reaction is combined with the reaction of the isocyanate group with water, whereby foam is obtained by the formation of urethane bonds and by simultaneous development of carbon dioxide gas resulting from the reaction with water. On the other hand, physical expansion utilizes part of the heat of the polymerization reaction to vaporize a chemically inert, low-boiling point liquid (blowing agent).

As foaming agents, products such as hydrocholorofluorocarbons (HCFC) are used, in combination with water or alone. The foaming agent is added to polyols and its action appears by vaporization induced by the heat developed by the main reaction, which is of exothermic type. All the other additives and catalysts are also added to the polyols.

The most widely used isocyanates in the production of these foams are TDI (toluene diisocyanate) isomers and MDI (diphenylmethane diisocyanate polymer). Generally a 80/20 mixture of the two TDI isomers is used for synthesis of flexible foams, whereas the MDI is more frequently used in the production of rigid foams.

Generally, integral self-skinning foams are used in seats and bicycle saddles. These foams are characterized by a cellular inner structure and a non- cellular outer surface, and are formed in a mold in a single step. The principle of their synthesis is the use of halogenated hydrocarbons as a blowing agent, without water, as well as the use of molds having cold metal walls. As the foam contacts the cold wall of the mold, the blowing agent condenses at the operating pressure (1 -4 bar). This will cause a solid outer cover to be formed, whereas the reaction mixture is still hot inside and cures into foam. Polyol oligomers are used whose molecular weight ranges from 3000 to 6500, whereas for isocyanate the choice depends on the type of process. TDI isocyanates are typically used for bicycle saddles.

The formulation that is used for making the pad 4 and the cover 7 of the human body support comprises at least one fossil-derived polymer material and at least one renewable source-derived material.

Preferably, the amount of renewable source-derived polymer materials in the formulation ranges from 5% to 60%, preferably from 1 0% to 40% and more preferably from 1 5% to 35% by weight.

A peculiar characteristic of the material is that the materials in the above formulation are selected such that the carbon footprint, as defined in accordance with the standard ISO 14067 in terms of amount of carbon dioxide equivalent (CO₂e) is relatively low and the percent radiocarbon-14 (pMC), as defined according to the standard ASTM D6866 is relatively high.

Specially referring to the pad 4, the amount of carbon dioxide equivalent (CO2e) associated with 1 kg of the formulation to form the pad is < 9.5kg, and preferably ranges from 9.3kg to 1 .9kg, more preferably from 4.9kg to 3.5kg.

Also, the percent radiocarbon-14(pMC) associated with 1 kg of the formulation to form the pad 4 is > 0.01 %, and preferably ranges from 60% to 5%, more preferably from 40% to 1 0%.

Specially referring to the cover 7, the amount of carbon dioxide equivalent (CO2e) associated with 1 kg of the formulation to form the cover is < 9.5kg, and preferably ranges from 9.3kg to 1 .9kg, more preferably from 3.6kg to 2kg.

Also, the percent radiocarbon-14 (pMC) associated with 1 kg of the formulation of the cover 7 is > 0.01 %, and preferably ranges from 70% to 30%, more preferably from 60% to 40%. Specially referring to the pad 4, the lower layer 5 may be a foam obtained from a foamed polymer preparation, such as a foamed polyurethane adapted to form a high-performance product.

Conveniently, the above mentioned polyurethane foam is selected with a relatively low Carbon Footprint value and a relatively high radiocarbon value pMC.

The above mentioned polyurethane preparation is obtained by mixing a polyol phase composed of a blend of polyols for integral PU and flexible PU with different molecular weights, an isocyanate phase composed of a blend of isocyanates for integral PU and flexible PU, a fossil source-based and renewable source-based additive phase.

Preferably, the polyols for integral PU has a molecular weight ranging from mw=4000 to mw=7000 and preferably of about mw=4500, and the polyols for flexible PU have a molecular weight ranging from 5000 to 6500 and preferably of about mw=6000.

The weight percent of the polyols for integral PU having a mw=4500 based on the total, preferably ranges from 40% to 0.01 %, more preferably from 25% to 1 5% and still more preferably from 1 7% to 5%.

The weight percent of the polyols for flexible PU having a mw=6000 based on the total, preferably ranges from 35% to 0.01 %, more preferably from 25% to 10% and still more preferably from 21 % to 5%.

The weight percent of the isocyanates for integral PU based on the total, preferably ranges from 30% to 1 0%, more preferably from 25% to 1 5% and still more preferably from 20% to 3%.

The weight percent of the isocyanates for flexible PU based on the total, preferably ranges from 20% to 0.01 %, more preferably from 1 5% to 5% and still more preferably from 10% to 3%.

The weight percent of the fossil source-derived additives based on the total, preferably ranges from 15% to 0.01 %, more preferably from 1 0% to 5% and still more preferably from 6% to 5%.

The use of renewable source-derived materials even in the production of polyurethane foams was also significantly promoted by the identification of alternative "bio-based" additives, which have a lower cost as compared with synthetic additives.

In this respect, in polyol-based formulations for integral foams and flexible foams, biological additives may be selected from glucides (carbohydrates), particularly from disaccharides.

Sucrose may be selected from disaccharides, in the form of "icing sugar".

Sucrose, i.e. 0₆Η ₂Ο₆, is known to be formed by the reaction of a glucose molecule with a fructose molecule and the release of a water molecule. The hydroxyl groups of sucrose bond with those of isocyanate thereby assisting polymerization of the polyurethane mixture.

The amount of "icing sugar" that can be added to the polyol-based formulation is limited because, as the percentage of this bio-based additive increases, firmness increases, and resilience decreases.

In terms of costs, the use of this bio-based additive is advantageous due to the reduced cost of the material, i.e. about 1€/kg.

Furthermore, the renewable source-derived additives may include additives selected from the group comprising plasticizers, cross-linking agents, catalysts, foaming agents.

Particularly, plasticizers may comprise ricinoleic acid, whose weight percent ranges from 15% to 1 8%, and is preferably of about 1 7%.

For example, the ricinoleic acid may be added by mixing castor oil as it is with the other components of the pad 4.

Nevertheless, the use of castor oil as it is was experimentally found to lead to the formation of so-called "compact" polyurethane compounds, having a Shore C hardness of about 60, as measured according to the standard ASTM 2240.

Therefore, the resulting pad 4 is not adequately comfortable, as it exhibits relatively high density and hardness.

Conversely, the use of plasticizers containing hydrogenated castor oil both for the lower portion 5 of the pad 4 and for the gel 6 was found to improve the mechanical properties and the softness of the pad of the support, thereby increasing comfort for the user.

Particularly convenient results were obtained using plasticizers comprising acetylated monoglycerides, particularly derived from completely hydrogenated castor oil.

A preferred component may be the acetic ester of monoglyceride (also known as acetylated monoglyceride) with CAS number 736150-63-3.

The use of such additives will provide a lower layer 5 with a Shore C hardness, as measured according to the standard ASTM 2240, ranging from 30 to 50, preferably from 40 to 45, and an upper layer having a Shore C hardness, as measured according to the standard ASTM 2240 ranging from 1 to 1 0 and preferably of about 5.

The weight percent of the renewable source-derived additives based on the total, preferably ranges from 55% to 0.01 %, more preferably from 45% to 10% and still more preferably from 33% to 10%.

The weight percent of the renewable source-derived plasticizers based on the total, preferably ranges from 30% to 0.01 %, more preferably from 25% to 5% and still more preferably from 1 7% to 5%.

The weight percent of the renewable source-derived fillers based on the total ranges from 25% to 0.01 %, more preferably from 20% to 5% and still more preferably from 1 6% to 5%.

As for the upper layer 6 of the pad 4, it may comprise a polyurethane gel having a relatively low Carbon Footprint value and a relatively high radiocarbon value pMC.

Particularly, the polyurethane gel may be obtained by mixing a polyol phase comprising a polyol for flexible PU having a molecular weight mw=6000, an isocyanate phase composed of a blend of isocyanates for integral PU and flexible PU, with the addition of a fossil additive phase and a renewable source- based additive phase.

Particularly, the weight percent of the polyols for flexible PU having a mw=6000 based on the total, may range from 95% to 25%, more preferably from 70% to 50% and still more preferably from 60% to 5%.

The weight percent of the fossil source-derived additives based on the total, preferably ranges from 2% to 0.01 %, more preferably from 1 .75% to 0.25% and still more preferably from 1 % to 0.5%. The weight percent of the renewable source-derived additives based on the total, preferably ranges from 70% to 0.01 %, more preferably from 45% to 25% and still more preferably from 35% to 5%.

The weight percent of the isocyanates for integral PU based on the total, preferably ranges from 5% to 0.01 %, more preferably from 4% to 1 % and still more preferably from 2.5% to 1 %.

The weight percent of the isocyanates for flexible PU based on the total, preferably ranges from 2% to 0.01 %, more preferably from 1 .75% to 0.25% and still more preferably from 1 % to 0.5%.

The configuration of the product of this invention allows the provision of human body supports, and particularly bicycle saddles, characterized by a renewable source-derived (i.e. bio-based) material content that may even be 44% higher than in similar competitors' products, such as the saddle structure as disclosed and claimed in the European patent application EP 21 39751 .

Also, it allows the provision of saddles having a carbon-footprint equivalent

(CO2e) content of about 2.94 kg per kilogram of the saddle against 4.1 1 kg per kilogram of similar commercially available products, such as the above mentioned saddle structure as disclosed and claimed in EP2139751 .

In other words, similar commercially available saddles of the above mentioned type have a 40% higher carbon footprint as compared with the saddles constructed according to the teachings of the invention.

Two examples of polyurethane foam are provided below for the lower layer 5 of the padding, as obtained with products sold by Dow Chemical, with different amounts of renewable source-derived polymer materials, according to the following percentages, which are determined with reference to a 1 00% weight of the polyurethane foam.

EXAMPLE 1

A) POLYOL phase

A1 ) SPECFLEX NR 961

A.1 .1 - SPECFLEX NR 914 (Preparation for INTEGRAL)

INTEGRAL POLYOL phase with mw = 4500

VORANOL CP 471 1 (69%) 1 6.48% SPECFLEX NC 700 (1 3%) 3.1 0% Additives for INTEGRAL PU

MONOETHYLENE GLYCOL (cross-linking agent) 2.31 %

WATER (foaming agent) 0.1 1 % VORALUX HT 326 (catalyst) 0.1 1 %

PLS 91 2 NERO (coloring pigment) 0.88%

SOLKANE 245 (foaming agent) 0.88% A.1 .2 ) Preparation for FLEXIBLE

FLEXIBLE POLYOL phase with mw = 6000

VORANOL CP 6001 23.88%

Additives for FLEXIBLE PU

MONOETHYLENE GLYCOL (cross-linking agent) 1 .67%

WATER (foaming agent) 0.08%

VORALUX HT 326 (catalyst) 0.08% PLS 91 2 NERO (coloring pigment) 0.64%

SOLKANE 245 (foaming agent) 0.64% A.2) RENEWABLE source-derived phase

A.2.1 ) Preparation with PLASTICIZING function

RICINOLEIC Acid 1 7.80% Additives for INTEGRAL/FLEXIBLE PU

MONOETHYLENE GLYCOL (cross-linking agent) 0.57%

VORALUX HT 326 (catalyst) 0.14%

SOLKANE 245 (foaming agent) 1 .1 3% B) ISOCYANATE phase : SPECFLEX NE 432

SPECFLEX NE 135(isocyanate for FLEXIBLE) 1 9.70%

SPECFLEX NE 145(isocyanate for INTEGRAL) 9.80% EXAMPLE 2

A1 ) SPECFLEX NR 961

A.1 .1 - SPECFLEX NR 914 (Preparation for INTEGRAL) INTEGRAL POLYOL phase with mw = 4500

VORANOL CP 471 1 (69%) 1 2.14%

SPECFLEX NC 700 (1 3%) 2.29% Additives for INTEGRAL PU

MONOETHYLENE GLYCOL (cross-linking agent) 1 .71 %

WATER (foaming agent) 0.08%

VORALUX HT 326 (catalyst) 0.08% PLS 91 2 NERO (coloring pigment) 0.65%

SOLKANE 245 (foaming agent) 0.65% A.1 .2 ) Preparation for FLEXIBLE

FLEXIBLE POLYOL phase with mw = 6000

VORANOL CP 6001 7.60% Additives for FLEXIBLE PU

MONOETHYLENE GLYCOL (cross-linking agent) 1 .22%

WATER (foaming agent) 0.06%

VORALUX HT 326 (catalyst) 0.06%

PLS 91 2 NERO (coloring pigment) 0.46% SOLKANE 245 (foaming agent) 0.46%

A2) RENEWABLE source-derived phase

PLASTICIZER preparation

RICINOLEIC Acid 1 6.00% Additives for INTEGRAL/FLEXIBLE PU

MONOETHYLENE GLYCOL (cross-linking agent) 0.20%

VORALUX HT 326 (catalyst) 0.04%

SOLKANE 245 (foaming agent) 0.40% Preparation with INERT FILLER

ICING SUGAR 1 6.00% B) ISOCYANATE phase : SPECFLEX NE 432

SPECFLEX NE 135(isocyanate for FLEXIBLE) 1 9.70%

SPECFLEX NE 45(isocyanate for INTEGRAL) 9.80%

Claims

1 . A human body support structure, such as a saddle or seat for a vehicle or a similar machine, comprising:

- a shell (2);

a pad (4) overlying said shell;

a cover (7) for covering said pad (4);

wherein said pad (4) and/or said cover (7) are made from a formulation comprising at least one fossil-derived polymer material and at least one renewable source-derived material,

wherein the materials in said formulation are selected such that the carbon footprint, as defined in accordance with the standard ISO 14067 in terms of amount of carbon dioxide equivalent (CO2e) per unit weight of the formulation is relatively low and the percent radiocarbon-14 (pMC), as defined according to the standard ASTM D6866 per unit weight of the formulation is relatively high,

wherein said formulation for forming the lower layer (5) of the pad (4) comprises a foamed polymeric preparation comprising a polyol phase, an isocyanate phase, an additive phase, and a plasticizer phase,

wherein said additive phase comprises fossil source-derived and renewable source-derived additives, said renewable source-derived additives comprising additives selected from the group comprising plasticizers, crosslinking agents, catalysts, foaming agents,

wherein said plasticizers are derived from hydrogenated castor oil.

2. A structure as claimed in claim 1 , wherein said plasticizers comprise acetylated monoglycerides derived from hydrogenated castor oil.

3. A structure as claimed in claim 2, wherein said lower layer (5) of said pad (4) comprises a foamed polymer preparation with a polyurethane foam for integral PU and flexible PU containing said plasticizers derived from hydrogenated castor oil.

4. A structure as claimed in any of the preceding claims, wherein the amount of renewable source-derived polymer materials in said formulation ranges from 5% to 60%, preferably from 10% to 40% and more preferably from 1 5% to 35%.

5. A structure as claimed in any of the preceding claims, wherein said plasticizers are provided in said lower layer (5) to impart a Shore C hardness ranging from 30 to 50, preferably from 40 to 45, as measured according to the standard ASTM 2240, to the polyurethane foam.

6. A structure as claimed in any of the preceding claims, wherein said upper layer (6) of the pad (4) comprises a polyurethane gel, said plasticizers being provided in said polyurethane gel to impart thereto a Shore C hardness ranging from 1 to 1 0, preferably of about 5, as measured according to the standard ASTM 2240.