COMPOSITION COMPRISING GROUND PLANT SEED, PROTEIN ISOLATE, STARCH OR A MIXTURE THEREOF, METAL OXIDE AND PLASTICIZER

Abstract

The invention relates to a composition, such as an adhesive and/or injectable composition, comprising at least or consisting of: ground plant seeds, protein isolate, starch or mixture thereof, a metal oxide, a plasticizer, and optionally, water.

The invention also concerns an article and a lignocellulosic-based composite comprising said composition.

Claims

1. A composition comprising or consisting of: ground plant seeds, protein isolate, starch or a mixture thereof, a metal oxide, a plasticizer, and optionally, water.

2. The composition of claim 1, wherein the plant seeds of the ground plant seeds are whole seeds.

3. The composition according to claim 1, wherein said ground plant seeds comprise at least 3% proteins by weight based on the weight of the ground plant seeds.

4. The composition according to claim 1, wherein said ground plant seeds, protein isolate, starch or a mixture thereof are from a plant belonging to one or several of palm, safflower, sunflower, rape, canola, mustard, Camelina, hemp, soybean, lupine, pea, flax, and/or cotton.

5. The composition according to claim 1, wherein said metal oxide is MgO, ZnO, TiO.sub.2, Fe.sub.2O.sub.3, Al.sub.2O.sub.3, or SiO.sub.2, or a mixture thereof.

6. The composition according to claim 1, wherein said metal oxide represents from 1% to 50% by weight based on the weight of the ground plant seeds, protein isolate, starch or mixture thereof.

7. The composition according to claim 1, wherein said plasticizer is at least one polyol or a mixture of polyols.

8. The composition according to claim 1, wherein said composition is injectable and comprises or consists of: ground plant seeds chosen from ground whole pea seeds, sunflower seed meal, rapeseed or canola seed meal and/or soy meal; MgO as metal oxide, in a quantity of 3% to 10% by weight based on the weight of the ground plant seeds; glycerol as plasticizer, in a quantity of 5% to 40% by weight, based on the total weight of the injectable composition; and optionally water.

9. The composition according to claim 1, that is adhesive, wherein said plasticizer represents 20% to 60% by weight based on the weight of the ground plant seeds, protein isolate, starch or mixture thereof.

10. The composition according to claim 1, wherein said composition is adhesive and comprises or consists of: ground plant seeds, wherein plant seeds are chosen from whole pea seeds, sunflower seeds meal, rapeseed or canola seed meal or soy meal; a metal oxide chosen from ZnO, SiO.sub.2 or MgO, or a mixture thereof, in a quantity of 10% by weight based on the weight of the ground plant seeds; glycerol as plasticizer, in a quantity of 40% by weight based on the weight of the ground plant seeds; and optionally, water.

11. A process for preparing a composition according to claim 1, wherein in a first step, ground plant seeds, protein isolate, starch or a mixture thereof are mixed with at least one metal oxide, until complete mixing and, in a second step, at least one plasticizer is added, water being optionally added during the first or second step.

12. A lignocellulosic-based mixture comprising the composition according to claim 1, and a lignocellulosic material.

13. A lignocellulosic-based mixture comprising or consisting of: lignocellulosic material, and 10%-95% by weight of dry matter of the composition according to claim 1, by weight of the lignocellulosic-based mixture.

14. A method for preparation of a lignocellulosic-based composite comprising mixing the composition according to claim 1 and a lignocellulosic material.

15. A process for preparing an article comprising the steps of: (i) filling an extruder with the composition of claim 1, and (ii) extruding the composition into a mold, wherein the composition is an injectable composition.

16. The composition according to claim 1, wherein said ground plant seeds, protein isolate, starch or a mixture thereof are from ground whole pea seeds.

17. The composition according to claim 1, wherein said metal oxide is MgO.

18. The composition according to claim 1, wherein said plasticizer is glycerol.

19. The lignocellulosic-based mixture of claim 12, wherein the lignocellulosic material is wood.

Description

[0187] The invention will be better understood in the light of the following examples, given by way of illustration, with reference to:

[0188] FIG. 1 that is a diagram illustrating the modulus of rupture (MOR) values of composites based on wood and a matrix composed of pea flour and SiO.sub.2 (PF-SiO.sub.2) depending on the wood/matrix ratio;

[0189] FIG. 2 that shows composites prepared with different wood/matrix (W/PF-SiO.sub.2) ratios of (A) 95/5; (B) 90/10 and (C) 60/40;

[0190] FIG. 3 that is a diagram illustrating the effect of different metal oxides on Wood/Pea Flour matrix (W/PF), 60/40 wt/wt %, composites modulus strength (A) and thickness swelling properties (B);

[0191] FIG. 4 that is a diagram illustrating the effect of glycerol content on Wood/Pea Flour-SiO.sub.2 composites modulus strength (A) and thickness swelling properties (B);

[0192] FIG. 5 that is a diagram illustrating the effect of different metal oxides on plasticized W/PF-Gly40 (60 wt % wood/40 wt % PF-Gly40) composites modulus strength (A) and thickness swelling properties (B);

[0193] FIG. 6 that is a diagram illustrating the MOR (A) and TS (B) properties of composites based on wood and a matrix composed of ground whole pea seeds (pea flour), soybean meal, sunflower meal or ground corn distillers grains (corn flour), either native or mixed with SiO.sub.2 and/or with glycerol;

[0194] FIG. 7 that is a diagram illustrating the injection pressure measured during injection of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix;

[0195] FIG. 8 that is a diagram illustrating the density of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix;

[0196] FIG. 9 that is a diagram illustrating the density of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the injection pressure measured during its injection;

[0197] FIG. 10 that is a diagram illustrating the maximum flexural stress (or MOR) of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix;

[0198] FIG. 11 that is a diagram illustrating the flexural modulus of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix;

[0199] FIG. 12 that is a diagram illustrating the maximum tensile stress of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix;

[0200] FIG. 13 that is a diagram illustrating the Young modulus of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix;

[0201] FIG. 14 that is a diagram illustrating the thickness swell (TS) properties at ambient temperature of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix;

[0202] FIG. 15 that is a diagram illustrating the TS properties at 80° C. of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix;

[0203] FIG. 16 that is a diagram illustrating the water adsorption (WA) properties at ambient temperature of a matrix consisting of ground whole pea seeds (pea flour) mixed with MgO, and water and/or glycerol, depending on the amount of water and/or glycerol in the matrix.

EXAMPLE 1

Biobased Composites from Plant Seed Flour, SiO.SUB.2 .and Glycerol

[0204] Materials:

[0205] Whole yellow peas (Pisum sativum) and soybean meal (Glycine max) were purchased from Sanders (France) and ground in order to obtain pea flour (PF) with a Volume Diameter (Dv) of Dv(10) of 7 μm, Dv(50) of 25 μm, and Dv(90) of 77 μm and soy flour (SF) with a diameter of Dv(10) of 15 μm, Dv(50) of 43 μm, and Dv(90) of 115 μm.

[0206] Total crude protein content of PF and SF obtained using Kjeldhal procedure with a nitrogen-to-protein conversion factor of 6.25 was 19% and 48%, respectively.

[0207] Glycerol was provided by Oleon (France) and used as plasticizer. Magnesium oxide, MgO (40 μm) and silicon dioxide, SiO.sub.2 (250 μm) were purchased from Fluka.

[0208] Zinc oxide, ZnO (30 nm) was purchased from Acros Organics. Wood particles were spruce from Brunswick (Germany) with average particle size of 1.25-3.15 mm and supplied by Fraunhofer Institute for Wood Research.

[0209] Matrices Preparation:

[0210] Matrix Based on Proteaginous Materials Reinforced with Metal Oxides

[0211] Reinforced pea flour based matrices were prepared by blending PF with different metal oxides. Matrices were prepared by adding 10% by weight, based on pea flour weight, of SiO.sub.2, MgO or ZnO to pea flour and the whole mixtures were dispersed into distilled water with a total solid content of 60 wt %. The PF-SiO.sub.2, PF-MgO and PF-ZnO matrices were further used to prepare the composites.

[0212] A similar procedure was carried out using soy flour. A solution of soy flour and 10 wt % SiO.sub.2 (SF-SiO.sub.2), based on soy flour weight, with total solid content of 60% was prepared and used as matrix for composites.

[0213] Plasticization of Matrix Based on Proteaginous Materials Reinforced with Metal Oxides

[0214] Glycerol was used in the formulation to improve softness (or elasticity) of the PF-SiO.sub.2 based composites.

[0215] Different amounts of glycerol were added to PF-SiO.sub.2 blend (0, 5, 10, 30, 40 and 50% based on dry weight of PF) and the mixtures were thoroughly blended at room temperature for 10 min to obtain PF-SiO.sub.2-Glyx, wherein x represents the percentage of glycerol by weight based on ground plant seed dry weight (x being comprised between 0 and 50).

[0216] For SF matrix, only one amount of glycerol was tested (40 wt % based on SF dry weight) and added to the SF-SiO.sub.2 mixture and the whole solution was blended for 10 min at room temperature to obtain SF-SiO.sub.2-Gly40 matrix.

[0217] Preparation of Composites:

[0218] Different composites were prepared by mixing PF-SiO.sub.2 matrix solution to wood particles with different ratios in a Minneapolis Planetary mixer, in order to determine the best matrix and wood particles amounts.

[0219] For the composites based on PF-MgO-Gly40, PF-ZnO-Gly40 or PF-SiO.sub.2-Gly40 matrices, the amount of matrix and wood particles was kept at 40 wt % dry matter on the weight of composite and 60 wt % dry matter on the weight of composite, respectively.

[0220] All blends were then hot-pressed at 150° C., for 3 min at pressure of 15 metric tons (MeT), using a CARVER hot press, to prepare composites with 4 mm thickness and 700 kg/m.sup.3 density.

[0221] Mechanical Property Testing:

[0222] The standards as stated in this application are those current at the date of filing.

[0223] Mechanical Strength:

[0224] The measurement is carried out by a 3-point bending test intended to assess the maximum stress, and the modulus of rupture (MOR). This measurement is based on the standard NF EN 310 and is carried out on an Imal apparatus (IBX 700, Imal SRL, Italy). The modulus of rupture (MOR) was determined on rectangular strips of 148×40×4 mm (conditioned at 65% relative humidity and 20° C.) at a crosshead speed of 5 mm/min. The distance between supports and the width of each support are 120 mm and 54 mm, respectively. The average MOR were obtained on the basis of triplicate.

[0225] Water Resistance:

[0226] The measurement of swelling in thickness of the wood board after total immersion in water (according to standard NF EN 317) is carried out at ambient temperature, the thickness measurements being carried out at t0, t+2 hours, on average on 3 samples and is carried out on an Imal apparatus (IBX 700, Imal SRL, Italy).

[0227] The dimensional stability of composites with a nominal side length 50.0×50.0×4 mm (conditioned at 65% relative humidity and 20° C.) was determined by measuring the increase in thickness of the specimens after immersion in water at 2 h. The specimens were immersed in water at room temperature and after a period of 2 h, the samples were surface dried using blotting paper and then immediately weighed.

[0228] The percentage of thickness swelling after 2 hours (TS.sub.2h) was calculated as shown in equation (1):

[00001]$T{S}_{2h}\left(\%\right)=\frac{t2-t1}{t1}\times 100$

[0229] where t1 is thickness at specimen center before soaking and t2 is the thicknesses of test specimens after soaking for 2 h.

[0230] Results

[0231] This example is focused on the study of the thermal and mechanical behavior of reinforced agro-materials based on pea flour. Composites where first prepared by mixing different ratios of wood particles and PF-SiO.sub.2 matrix and the mechanical performances of the final composites were evaluated and compared.

[0232] The modulus of rupture (MOR) results obtained from the three-point bending tests are illustrated in FIG. 1.

[0233] The MOR corresponds to the fibers resistance to bending deformation and is an important parameter of the mechanical properties. When the amount of matrix was lower than 10% wt, the composites had extremely poor properties, and exhibited a MOR value of 3 MPa.

[0234] But increasing amount of PF-SiO.sub.2from 10 wt % to 40 wt % involved increasing MOR to 11 MPa and 26 MPa, respectively, and thus increased composite strength.

[0235] However, when the matrix content exceeds 40% wt, the composites remained extremely brittle. Based on these results, the optimal matrix amount was determined as 40 wt % mixed with 60 wt % of wood particles.

[0236] These mechanical characterizations are in good correlation with macroscopic observations (see FIG. 2).

[0237] At low matrix level of 5% wt (A), the surface of composite was irregular and rough but when matrix level was over 10 wt % (B and C) the composites where strong with a homogeneous surface aspect.

[0238] As it can be seen on FIG. 3, W/PF-SiO.sub.2 exhibited higher MOR value (26 MPa) compared to W/PF (15 MPa) showing the good reinforcement effect of SiO.sub.2 particles probably due to strong interactions between SiO.sub.2 particles and proteins and starch molecules of pea flour.

[0239] The silicon dioxide particles are likely to bond with hydroxyl groups and through possible hydrogen or Van der Waals bonds of starch or proteins macromolecules.

[0240] The strengthening molecular forces between particles and pea flour molecules enhance the composites properties as determined by flexural modulus.

[0241] Composites were also prepared from PF blended with different metal oxides such as MgO and ZnO particles and the final properties were compared to that obtained from SiO.sub.2 filler (see FIG. 3). All formulations with metal oxides exhibited higher strength values and lower thickness swelling. However, the highest strength value was found with SiO.sub.2.

[0242] W/PF composites are hard and brittle. Therefore, it is necessary to use a plasticizer in the production of composites to increase the softness (or elasticity). The most common plasticizer used in composites fabrication is glycerol. Different amounts of glycerol were thus added into PF-SiO.sub.2 formulation and the mechanical properties and water resistance were evaluated and compared (see FIG. 4).

[0243] As clearly shown, adding glycerol weakened the mechanical properties of the composites due to the plasticization effect.

[0244] However, surprisingly, for high amount of glycerol over 30 wt %, the water resistance of the composites was improved.

[0245] Glycerol is a hydrophilic molecule that generally increase water uptake. This improvement of water resistance could be due to some interactions between hydroxyl groups of glycerol and pea flour molecules, decreasing the number of polar functions in the overall material.

[0246] The composites prepared from PF-SiO.sub.2 and 40 wt % of glycerol exhibited interesting MOR value and great water resistance.

[0247] Moreover, the final composites exhibited a smooth and homogeneous surface and showed good flexibility.

[0248] FIG. 5 shows the MOR and thickness swelling properties of plasticized composites (with 40% wt of glycerol) prepared with PF matrix reinforced with different metal oxides.

[0249] It is shown that glycerol lowered the MOR values of all materials due to plasticization effect as observed previously.

[0250] However, compared to W/PF-Gly40 composite, the reinforced matrices exhibited higher MOR values, giving composites with satisfactory mechanical properties.

[0251] Moreover, it is shown that blending with metal oxides further increased the swelling properties of the materials. The bests results were find with SiO.sub.2 particles.

CONCLUSION

[0252] Hybrid organic-inorganic matrices based on pea flour and SiO.sub.2, ZnO or MgO are presented as effective and sustainable matrices for composites. The composites exhibited higher strengths and better water resistance compared to W/PF composite.

[0253] Moreover, addition of glycerol molecules into the formulation not only increased flexibility of the whole composites but also increased the water resistance despite the high hydrophilic properties of glycerol molecules.

[0254] Moreover, PF blended to SiO.sub.2 and glycerol obtains satisfactory flexural strength, over 13 MPa (see FIG. 4A).

EXAMPLE 2

Biobased Composites

[0255] A lignocellulosic-based composite was prepared: [0256] 45% w/w of wood; [0257] 22% w/w of additional water; [0258] 22% w/w of pea flour; [0259] 2.2% w/w of SiO.sub.2; and [0260] 8.8% w/w g of glycerol;

[0261] the weight being given based on the weight of the lignocellulosic-based composite.

EXAMPLE 3

Comparison of Composite Mechanical Properties Prepared from Different Raw Materials

[0262] Materials:

[0263] Soybean meal, sunflower meal (by-product obtained after pressure and solvent (hexane) extraction of oil from seeds) and corn distillers grains (the solid residue left over after distillation in corn ethanol production) were purchased from Sanders (France) and ground thanks an impact mill from Hosokawa in order to obtain soy flour (SF), with a diameter of Dv(10) of 15 μm, Dv(50) of 43 μm and Dv(90) of 115 μm; sunflower flour (SuF)) with a diameter of Dv(10) of 6 μm, Dv(50) of 32 μm and Dv(90) of 150 μm and corn flour (CF) with a diameter of Dv(10) of 7 μm, Dv(50) of 31 μm and Dv(90) of 115 μm. Total crude protein content of SF, SuF and CF obtained using Kjeldhal procedure with a nitrogen-to-protein conversion factor of 6.25 was 48%, 40% and 20%, respectively.

[0264] Preparation of Composites:

[0265] Wood composites were prepared from different raw materials and compared with those prepared from pea flour. Different matrix formulations were tested. The composites were prepared using native raw materials, blended with SiO.sub.2, blended with Glycerol or blended with SiO.sub.2 and glycerol, and are dispersed into distilled water with a total solid content of 60 wt %. The amount of SiO.sub.2 and glycerol was 10 wt % and 40 wt %, respectively, based on raw material dry weight. The ratio of matrix and wood particles was kept at 40 wt % dry matter on the weight of the composite and 60 wt % dry matter on the weight of the composite, respectively. All blends were dry with an oven to decrease the amount of water (30 min at 50° C.) and get a residual moisture content lower than 12 wt % of dry wood. Then they were hot-pressed at 150° C., for 3 min at pressure of 15 metric tons (MeT), using a CARVER hot press, to prepare composites with 4 mm thickness and 700 kg/m.sup.3 density.

[0266] Mechanical Property Testing:

[0267] Three-point bending tests were determined using an Imal apparatus (IBX 700, Imal SRL, Italy) and based on the standard NF EN 310. The modulus of rupture (MOR) was determined on rectangular strips of 148×40×4 mm (conditioned at 65% relative humidity and 20° C.) at a crosshead speed of 5 mm/min. The distance between supports and the width of each support are 120 mm and 54 mm, respectively. All experiments were repeated at least three times. Averages of the data and their standard deviations were calculated and presented in figures as error bars.

[0268] Water Resistance:

[0269] The measurement of swelling in thickness of the wood board after total immersion in water (according to standard NF EN 317) is carried out at ambient temperature using an Imal apparatus (SW200 or BT200, Imal SRL, Italy).

[0270] The dimensional stability of composites with a nominal side length 50.0×50.0×4 mm (conditioned at 65% relative humidity and 20° C.) was determined by measuring the increase in thickness of the specimens after immersion in water at 2 h. The specimens were immersed in water at room temperature and after a period of 2 h, the samples were surface dried using blotting paper and then immediately weighed.

[0271] The percentage of thickness swelling after 2 hours (TS.sub.2h) was calculated as shown in equation (1) (see Example 1).

[0272] Results

[0273] FIG. 6A shows the modulus of rupture (MOR) and FIG. 6B the thickness swelling (TS) properties of different composite formulations obtained from pea flour, soy flour, sunflower flour and corn flour. Except corn flour, all raw materials blended with SiO.sub.2 nanoparticles exhibited higher MOR value and lower thickness swelling properties compared to the native counterpart. However, for all materials, addition of glycerol weakened the mechanical properties of the composites due to the plasticization effect lowering the MOR values but improved the water resistance of the composites.

[0274] The composites prepared from soy flour, sunflower flour and pea flour blended with 10% of SiO.sub.2 and 40% of glycerol exhibited interesting MOR value and good water resistance. However, when corn flour was used in the formulation, poor mechanical properties were obtained, maybe due to the additional process steps that were carried out to obtain corn distillers grain (in particular, fermentation and distillation) that can result in a low interaction between this raw material and SiO.sub.2 nanoparticles. The highest MOR value was found with pea flour as raw material while the TS properties were similar for all materials. Based on the results, pea flour is one of the most interesting raw materials to prepare the biobased composites.

EXAMPLE 4

Injection Molding of Composition for Bio Material End Use Application

[0275] The aim of this study is to evaluate the injectability of compositions and their associated performances by using various plasticizers to adjust mechanical performances and improve injectability. The compositions were obtained by mixing pea flour with magnesium oxide.

[0276] Raw Material:

[0277] For this study, a micronized pea flour (PF) with a d50 of 40 μm was used as a biopolymer, formulated with a 5% wt of a MgO powder (d50 of 10 μm) based on pea flour weight powder. The flour was obtained thanks to an impact mill from Hosokawa and the MgO was blended with pea flour thanks to a Gedu kettle. The PF was stirred at 35 rpm under room temperature. The MgO was introduced during 10 min in the kettle and kept running an additional 30 min until the blend PF+MgO looks homogeneous. Moisture content of the blend is at 9 wt % with respect to the dry weight of the composition.

[0278] Prior to injection molding, three types of additives have been combined with the PF+MgO blend:water (E), glycerol (G), and a blend 50/50 of water and glycerol (EG), in an amount ranging from 20 wt % to 35 wt % of the total composition (when water has been used, this percentage corresponds to the additional water and the moisture already present in the blend).

[0279] Blends of PF+MgO+additive have been done by pouring the additive into a 20 L plastic drum first and then with the blend of PF+MgO. The drum is first stirred gently with a spatula and then closed and stirred manually to incorporate the additive in the PF+MgO blend for about 5 min. A visual inspection is done to qualify the quality of the additive distribution by having some homogeneous “pellet” shape aspect. If the aspect is not good enough, the drum is reclosed and stirred again until the homogeneous “pellet” shape is achieved.

[0280] Equipment Used:

[0281] The injection press used was a Negri Bossi VE160-720 with an extruder screw diameter of 45 mm and an injectable volume of 360 cm.sup.3. The maximum injection pressure is 2000 bars and the closing force was 1600 kN (160 tons).

[0282] Screw temperature profile was set to 70° C.-120° C.-135° C. inside the extruder.

[0283] Nozzle temperature was set to 140° C. and mold temperature to 20° C. Only one condition (EG at 25 wt %) was set to a slightly different temperature profile (70° C.-120° C-145° C.), a slightly higher nozzle temperature (155° C.) and mold temperature (40° C.) because of some injectability limitation observed.

[0284] The mold used was designed to get one flexural and one tensile strength test sample following respectively ISO 178:2010 and ISO 527-4:1997.

[0285] All samples were conditioned at least 3 weeks to ensure weight stabilization (water evaporation) under 25° C. and 60% RH (Relative Humidity).

[0286] Test Method:

[0287] The injectability has been characterized by injection pressure measured during the trial (once it was possible to extrude the product).

[0288] Density was determined by measuring the sample dimension and sample weight after conditioning. Density then corresponds to the ratio between sample weight over sample volume in kg/m.sup.3.

[0289] Mechanical performances were measured following ISO 178:2010 and ISO 527-4:1997 standards.

[0290] Water resistance was done following NF EN 317 using water at room temperature for 24 h immersion time and with warm temperature (80° C.) for 5 minutes immersion time. Thickness and sample weight were measured before and after immersion in water to determine Thickness Swelling (TS) and Water Adsorption (WA).

[0291] Results:

[0292] Injectability Evaluation and Density

[0293] The first quantification of injectability was done by trying to inject various compositions (PF+MgO+additive) with various rate and type of additive. It was observed if the machine has the capacity to fill the mold and the results are in Table 1.

TABLE-US-00001 TABLE 1 Additive amount Water + (wt %) Water glycerol Glycerol 20.0 Yes No No 22.5 Yes No No 25.0 Yes Yes No 27.5 Yes Yes No 30.0 Yes Yes Yes 35.0 Yes Yes Yes

[0294] When “Yes” is indicated, it means that the product was thin enough to fill the mold.

[0295] On the contrary, “No” means that the product was too thick to fill the mold. One can observe that with water it was possible to process the product from 35 wt % down to 20 wt % of water. Below, filling the mold was too complicated. Glycerol could be used from 35 wt % down to 30 wt %. It means that glycerol is a less effective solvent to decrease the viscosity of the blend (PF+MgO) versus water. This is consistent with the fact that glycerol is a bigger molecule than water and could have difficulties to migrate into within the Pea flour (PF) network (proteins and starch particles).

[0296] The additive EG (50 wt % water and 50 wt % glycerol) enabled to go down to 25 wt % which is an intermediate level of performance regarding processability. To be noticed that at 25 wt % of EG in the composition (PF+MgO) required a slight increase of temperature profile, nozzle temperature and mold temperature.

[0297] To get a more quantitative assessment of processability versus additive nature and amount, the injection pressure was recorded and the results appear on FIG. 7.

[0298] One can observe a decrease of injection pressure with an increase of additive amount for a given additive type. For water, it decreases from 976 bar at 20 wt % to 434 bar at 35 wt %. The lowest pressure was obtained for 35 wt % of water, which confirms that water is the most efficient additive. At 30 wt % and 35 wt % of additive, all additive nature (water, glycerol and water+glycerol) could have been processed.

[0299] The additives could be ranked from the most effective to the less effective as follows: water then water and glycerol and then glycerol only. These results confirm the first assessment made with mold filling evaluation.

[0300] Density of samples was measured for each additive rate and nature as reported in FIG. 8.

[0301] One can observe a slight increase of density from 1380 to 1410 when the water amount increases from 20 wt % to 35 wt %. Same trends are observed with other additives in a smaller magnitude linked to a narrower range of additive amount.

[0302] Densities obtained with glycerol or glycerol+water were always lower. This observation could be linked to the difficulty to fill the mold that induces lower density, and the accumulated stress during the process which is released during conditioning and increases product dimension and thus decreases the density.

[0303] The density evolution could be correlated to injection pressure as represented on FIG. 9.

[0304] When water is used as an additive, one can observe a correlation between density and injection pressure. The lower is the injection pressure, the higher is the density and thus the higher is the additive amount. Glycerol and water blends seem to have a constant density whatever is the amount of additive used in the investigated range (from 25 wt % to 35 wt %). If glycerol is in the product, it could help to release stress accumulated during molding and keep dimension constant.

[0305] In conclusion, the inventors were able to inject the formulations by using only 20 wt % of additive when water is used as additive. Higher is the amount of additive, lower will be the injection pressure, better will be the mold filling and higher will be the density. Water is the most efficient additive. Glycerol is the less efficient additive and need to be used in a higher quantity (30 wt % or 35 wt %). Blend of glycerol and water exhibits intermediate results in term of processability.

[0306] Mechanical Performances:

[0307] Flexural tests have been conducted on each tested condition and are presented in FIGS. 10 and 11.

[0308] One can observe a decrease of maximum flexural stress with an increase of additive amount for water. On the opposite flexural modulus seems to be constant with the amount of additive used for water and blend of water and glycerol. Type of additive has a tremendous impact on flexural performance. When glycerol is used as an additive, one can observe a dramatic decrease of maximum flexural stress and flexural modulus. Same observation could be done with glycerol and water blend. This could be linked to the fact that after conditioning, water is released by the material and sample becomes more brittle (not plasticized). When glycerol is used, it remains within the sample and maintain plasticization effect and induces lower moduli and stress levels, which increases the softness (or elasticity) of the sample.

[0309] Tensile strength has be tested as well, and results are presented in FIGS. 12 and 13.

[0310] Young Modulus exhibits the same trends regarding impact of nature and amount of additive. Again, one can observe a tremendous effect of additive nature on Young modulus. Glycerol was the most effective additive after conditioning versus water (no desorption of glycerol during conditioning), due to its plasticization effect.

[0311] Blend of additives (water+glycerol) shows intermediate values.

[0312] Maximum stress exhibits a different trend. Glycerol remains the most efficient additive at 35 wt % to soften product versus water, but this gap is less pronounced.

[0313] The highest values were got with water and glycerol blend surprisingly.

[0314] In conclusion, water as an additive acts only during injection as it desorbs during conditioning and enables to get high level of mechanical performance. On the opposite glycerol enables to keep plasticization properties after sample conditioning and helps to soften the product. Blend of glycerol and water enable to adjust mechanical performances at the desired level and adapt formulation to product end-uses.

[0315] Water Resistance:

[0316] Water resistance was tested with a 24 h immersion test time in room temperature water. Sample thickness was measured before and after immersion. The thickness swell, which is the ratio of thickness variation over initial thickness (see equation (1)), is reported in FIG. 14.

[0317] The water adsorption percentage is reported in FIG. 16 and is calculated from the increase of sample mass before and after immersion divided by the initial sample mass (equation (2)):

[00002]$\begin{array}{cc}\mathrm{WA}=100\times \frac{m2-m1}{m1}& \left(2\right)\end{array}$

[0318] where m2 is the sample mass after immersion and m1 the sample mass before immersion.

[0319] Regarding experiments done with water as an additive, one can observe a decrease of thickness swelling with an increase of additive amount. This could be attributed to density increase and thus a decrease of water diffusion within the material during the immersion test. While water is replaced by glycerol, thickness swelling decrease even if density is almost constant or slightly lower. It means that the density is not the unique factor that could explain the positive impact of adding glycerol in the product (down to 13% at 35%). Blend of plasticizer (water and glycerol) exhibits intermediate results.

[0320] Immersion test was done also in hot water (80° C.) for 5 minutes. Results are reported in FIG. 15.

[0321] WA results exhibit the same trends. With glycerol, it was possible to achieve WA value down to 29.9% and 17.6% respectively to 30 wt % and 35 wt % of glycerol.

[0322] Results are reported in FIG. 16.

[0323] The hot water test is less discriminant than cold water because of a shorter immersion time. For this reason, thickness swelling is in a narrower range (all values are lower than 18%). The impact of additive amount in this case is not clearly observed. We can still observe better swelling performances when glycerol is used versus water (lower than 14%). There is a low value (10.8%) of thickness swelling for 27.5% of an additive blend of water and glycerol which is not expected.

CONCLUSION

[0324] The inventors were able to inject PF+MgO+additive blends. The type of additive needs to be chosen based on expected final mechanical performances. If only water is used (without glycerol) the end product will be too hard and too brittle.

[0325] Consequently, the amount of water can be adapted in a wide range of ratio based on targeted mechanical properties. For soft product, glycerol needs to be used. Its amount needs to be adapted to the level of mechanical performances desired.

[0326] Water could be added to glycerol to improve processability for intermediate softness product. This type of blend enables to tailor mechanical performance and use water to improve (if required) processability. Glycerol should be also the preferred additive once low thickness swelling in water is required.