EP3041987A1

EP3041987A1 - Method for waterproofing and lubricating plant fibres

Info

Publication number: EP3041987A1
Application number: EP14767044.2A
Authority: EP
Inventors: Sandrine Millot; Franck POCHON
Original assignee: Bluestar Silicones France SAS
Current assignee: Elkem Silicones France SAS
Priority date: 2013-09-03
Filing date: 2014-09-01
Publication date: 2016-07-13
Also published as: WO2015033029A1

Abstract

The present invention relates to a method for waterproofing and lubricating plant fibres using a silicone-based composition and to the use of said treated plant fibres in an insulating material.

Description

Process for water repellency and lubrication of plant fibers

The present invention relates to a process for hydrophobing and lubricating plant fibers with a silicone-based composition and the use of said treated vegetable fibers in an insulating material.

Technical area

The present invention is in the field of plant fiber processing methods.

State of the art

The decline in natural resources and the impact of different human activities on the environment have led to a reflection on sustainable development. In this context, buildings need to be energy efficient and use low environmental impact materials.

This is often called natural insulation or ecological insulation or green insulation to evoke non-polluting insulation materials and that in contrast to insulation from petrochemicals.

Natural insulation is derived from renewable materials, possibly available locally and recyclable.

Natural insulators based on plant fibers can combine ecological awareness and thermal performance, acoustic & humidity regulation and energy saving.

All these natural insulators make it possible to isolate the whole of a house, from the ground, to the ceiling, while passing by the envelope of the house or the external walls, the partitions.

Insulators made of vegetable or animal fibers include cork, linen wool, cellulose wadding, wood felt, hemp, coconut wool, sheep wool, feathers.

A plant fiber is a dead cell expansion that is mainly composed of polymers such as cellulose, hemicellulose, lignin and pectins. It is either isolated or grouped with others into a bundle. It is usually these bundles of fibers that are commonly referred to as plant fibers.

Vegetable fibers can come from different parts of the plant: seeds (cotton), stem or trunk (flax, hemp, wood), fruits (coconut) or leaves (agave, sisal).

The type of plant, the origin of the fibers and the conditions of growth are all factors playing on the variability of the performances of the vegetable fibers. In order to be able to use the vegetable fibers at the industrial level, it is necessary to extract them from the plant via an extraction process that depends on the location of the fibers in the plant and the target objective.

This process begins at the time of harvest. When the plant is mature, it is mowed or torn off and then stored immediately or deposited on the field where it is left for a longer or shorter time. Vegetable fibers are mainly derived from the stem of plants. The term "straw" commonly refers to one to several whole stems.

This stem is composed of 4 concentric zones: the outer bark, the liber in which are the bundles of fibers, xylem: internal marrow formed by lignin-rich cells and the lumen: hollow core. In order to be able to use plant fibers at the industrial level, it is necessary to extract them from the plant via an extraction process.

Retting is the maceration that is done to textile plants such as flax, hemp, etc., to facilitate the separation of the filamentous bark from the stem.

To obtain different vegetable fractions from straw, the so-called "classical" or "generic" extraction process is composed of three stages. Firstly, the decortication consists, by a mechanical operation exerted on the whole stem, to separate the ligneous material from the liber. Then, the different plant fractions obtained are separated. And finally the refining focuses on the beams to reduce the number of unit fibers per beam.

We then speak, according to their average length, plant fibers decimetric, centimeter, millimeter. The flours correspond to crushed vegetable fibers which are homogeneous and of small particle size (μιη).

Wood and annuals consist mainly of cellulose, hemicellulose (a substance similar to celluloses) and lignin. All of these; polymers constitutes more than 90% of the dry matter. Softwoods or hardwoods and annuals are distinguished by the proportions of each of these components expressed as a percentage by weight of fiber.

The average chemical composition of flax fibers is at least 60% cellulose, 15% hemicellulose and 1% lignin, respectively.

The average chemical composition of hemp fiber is 67% cellulose, 16% hemicellulose and 3% lignin.

The average chemical composition of softwood fibers (eg fir) is 48% cellulose, 20% hemicellulose and 27% lignin.

The average chemical composition of hardwood fibers (eg poplar) is 51% cellulose, 21% hemicellulose and 23% lignin.

Wood fibers are therefore characterized by a lignin content greater than 10%. Unlike yarn from spinning, that is to say the agglutination of fibers to form a long assembly intended for example weaving or knitting to obtain fabrics or knits, raw natural fibers are short and have little resistance or solidity.

Natural insulation comes in many forms: in panels, rolls or flakes in bulk (deposited or insufflated).

Thus, the application EP2392848 relates to a thermally and acoustically insulating material comprising a mixture of flax and hemp fibers.

It is known to treat these plant fibers to improve their properties, for example to protect them including rodents, to improve their resistance to moisture, fire and of course to facilitate their use.

Thus the use of dimethyl polysiloxane as water repellant is described in JP57191043 and the use of aminoalkyl silane as a binder is described in US8039110.

Their resistance to moisture must be constantly improved.

It is also important that the fibers be lubricated to improve their sliding properties and thus bring more comfort for users because their touch is then more pleasant and the amount of dust emitted during handling is lower. Improving the slip properties of plant fibers also facilitates the transport and organization of the fibers in the final material.

The slip performance of plant fibers must also be constantly improved.

An object of the present invention is to provide a process for hydrophobing and lubricating plant fibers to obtain plant fibers simultaneously meeting these needs, namely with improved moisture resistance and sliding properties.

For this purpose, the first object of the invention relates to a process for hydrophobing and lubricating vegetable fibers containing respectively from 40 to 80% by weight of cellulose, from 10 to 30% by weight of hemicellulose and from 0.1 to 30% by weight of lignin, expressed as a percentage by weight of fibers, characterized in that said plant fibers are brought into contact with at least one composition ( A) comprising at least one linear, cyclic or three-dimensional polyorganosiloxane (B) consisting of the following units:

Z-

wherein:

the symbols R ¹ , R ² and R ³ , which are identical and / or different, represent a monovalent hydrocarbon radical chosen from linear or branched alkyl radicals having from 1 to 4 carbon atoms, the linear or branched alkoxy radicals having from 1 to 4 carbon atoms, a phenyl radical and, preferably, a hydroxyl radical, an ethoxy radical, a methoxy radical or a methyl radical;

the symbols Z, identical or different, represent R ¹ and / or V;

the symbols V, identical and / or different functional groups, represent radicals of general formula (I):

-R ⁴ -N (R ⁵ ) (R ⁶ ) (I)

in which:

the symbol R ⁴ being a divalent hydrocarbon group having from 1 to 40 carbon atoms,

the symbol R ⁵ being a hydrogen atom or a monovalent hydrocarbon group having from 1 to 40 carbon atoms,

the symbol R ⁶ being a hydrogen atom or a radical of formula (II) below:

- [R ⁷ -N (R ⁸ )] _to R ⁸

in which:

the symbol R ⁷ being a divalent radical of formula (III) below:

- [C (R ⁸ ) (R ⁸ ) -] _b

- 0 <a <40

- b = 1, 2 or 3,

the symbol R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having from 1 to 40 carbon atoms;

- 10 <x <2000, and preferably 20 <x <2000,

- 0≤y <50, preferably 0 <y <10,

- 0≤ w <8, and with the additional provisos that at least one of Z represents V and that the composition contains neither free fatty acid nor polyorganosiloxane with a beta carboxy function.

The process for treating plant fibers with a composition (A) is simple and is particularly effective in optimizing both their water repellency and their lubrication.

Examples of useful radicals V according to the invention include the following radicals:

-CH ₂ -NH-C ₆ H ₅

-CH 2 -NH- (C 2 H 4 O) [C 2 H 3 (CH 3) O] _k H

-CaHe-NH-CEHS

-0 ₃ Η6-ΝΗ- (θ2Η4θ)] [θ2Η3 (ΟΗ ₃ ) 0] _k H

-C ₃ H ₆ -NH- (C ₂ H ₄ -NH) i (C ₂ H ₄ O) [C ₂ H ₃ (CH ₃ ) O] kH

-C3H6-NH-C2H4-NH-C6H5

-C3H6-NH-C2H4-NH-C6H1 ₁

-C3H6-NH-C2H4-NH- (C2H40); [C ₂ H3 (CH ₃ ) O] _k H

-C ₃ H ₆ -C ₅ H ₄ (CH 3) 4 NH 2

CH ₂ CH (CH ₃ ) CH ₂ -NH-C ₂ H ₄ -NH ₂

CH ₂ CH (CH ₃ ) CH ₂ -NH-C ₂ H ₄ -NH-C ₆ H ₅

CH ₂ CH (CH ₃ ) CH ₂ -NH-C ₂ H ₄ -NH-C ₆ H

-C ₃ H ₆ -NH-C ₂ H 4 -NH-C ₂ H ₄ -NH ₂

The indices i, j and k are identical or different integers having a value greater than or equal to 0 and less than or equal to 20 and the sum i + j + k is preferably between 0 and 30.

According to another preferred embodiment, the radical V is selected from the group consisting of the following radicals: - (CH ₂₎ ₃ -NH ₂ and - (CH ₂₎ 3 -NH- (CH ₂₎ 2 NH _2.

In the silicone nomenclature to describe, we speak of units M, D, T. The letter M represents the monofunctional unit of formula (CH3) 3 SiO / _2, the silicon atom being bonded to a single oxygen atom in the polymer comprising this unit. The letter D means a difunctional unit (CH ₃ ) ₂ SiO _2/2 in which the silicon atom is connected to two oxygen atoms. The letter T represents a trifunctional unit of the formula (CH ₃₎ Si0 _3/2, wherein the silicon atom is bonded to three oxygen atoms. These units may be functionalized, which has the consequence of replacing one or more radicals CH3 by another radical as mentioned above. We then speak of motifs M, D, T while specifying the specific radicals.

Preferably, the linear, cyclic or three-dimensional polyorganosiloxane (B) is a polydimethylsiloxane comprising M units bearing an ethoxy function and, on average, at least one D unit bearing a - (CH ₂ ) 3 -NH _{2 function} .

Even more preferably, the linear, cyclic or three-dimensional polyorganosiloxane (B) is a polydimethylsiloxane comprising M units bearing a methoxy function and, on average, at least one T unit carrying a function - (CH ₂ ) ₃ -NH - (CH ₂ ) ₂ -NH ₂ .

Preferably, the plant fibers used have a length of between 0.1 and 300 mm and preferably between 0.1 and 250 mm and even more preferably between 0.1 and 200 mm.

Preferably, the plant fibers used are composed respectively of 50 to 80% cellulose, 10 to 25% hemicellulose and 0.01 to 10% lignin (expressed as a percentage by weight of fibers). The flax or hemp fibers or their mixture are therefore preferably used.

According to another embodiment, the process for hydrophobing and lubricating plant fibers is characterized in that the composition (A) comprises:

at least one dispersing medium, and

at least one linear, cyclic or three-dimensional polyorganosiloxane (B) and as defined above.

The dispersing medium is an organic solvent that can be used for water repellency of plant fibers. Preferably the organic solvent is "white spirit" or heptane. The solvent or solvent mixture is present, preferably, in proportions of between 10 and 90% and preferably between 20 and 60% by weight relative to the total weight of the

composition. According to another embodiment, the method for hydrophobing and lubricating plant fibers is characterized in that said plant fibers are brought into contact with the composition (A) which is in the form of an aqueous dispersion of from minus one linear, cyclic or three-dimensional polyorganosiloxane (B) and as defined above. The water is present, preferably, in proportions of between 10 and 90% and preferably between 20 and 60% by weight relative to the total weight of the composition.

According to another particular embodiment, the composition (A) is in the form of a silicone emulsion in water which comprises:

at least one linear, cyclic or three-dimensional polyorganosiloxane (B) and as defined above,

water (E), and

- optionally at least one surfactant (T).

The nature of surfactant (T) will be easily determined by those skilled in the art, the objective being to prepare a stable emulsion. The anionic, cationic, nonionic and zwitterionic surfactants can be used alone or as a mixture.

It should be noted that the composition (A) according to the invention may also comprise protective colloids such as polyvinyl alcohol.

As anionic surfactant, mention may be made of the following surfactants:

the alkyl ester sulphonates of formula R ^a -CH (SO ₃ ) 1 -COOR ^b , where R ^a represents a C ₈ -C ₂₀ alkyl radical, preferably C ₁ -C ₆ alkyl, R ^{b is} a C 1 -C 6 alkyl radical, preferably C1-C3 and M an alkaline cation (sodium, potassium, lithium), substituted or unsubstituted ammonium (methyl-, dimethyl-, trimethyl-, tetramethylammonium, dimethylpiperidinium) or derived from an alkanolamine (monoethanolamine, diethanolamine, triethanolamine) ,

alkylsulphates of formula ROSO3M, in which R ^c represents a C10-C24, preferably C12-C20, alkyl or hydroxyalkyl radical, M representing a hydrogen atom or a cation of the same definition as above, as well as their derivatives; ethoxylenes (EO) and / or propoxylenes (PO), preferably having from 1 to 20 EO units,

- alkylamide sulfates of formula R ^d CONHROS0 ₃ M wherein R ^d represents an alkyl radical C2-C22, preferably Ce-C, R ^e alkyl, C ₂ -C _3l M representing a hydrogen atom or a cation with the same definition as above, as well as their ethoxylenated (EO) and / or propoxylenated (PO) derivatives, preferably having 1 to 20 EO units,

saturated or unsaturated C ₈ -C ₂ 4, preferably C ₁₄ -C ₂₀ fatty acid salts, C ₉ -C ₂₀ alkylbenzenesulfonates, and their ethoxylenated (EO) and / or propoxylenated (OP) derivatives, exhibiting preferably 1 to 20 EO units, - alkylbenzenesulfonates C9-C20, C8-C22 primary or secondary alkylsulfonates, alkylglycerol sulfonates, sulfonated polycarboxylic acids disclosed in GB-A-1 082 179, paraffin sulfonates, N-acyl N-alkyltaurates, mono- and dialkylphosphates, alkylisethionates, alkylsuccinamates, alkylsulfosuccinates, monoesters or diesters of sulfosuccinates, N-acyl sarcosinates, alkylglycoside sulfates, polyethoxycarboxylates, the cation being an alkali metal (sodium, potassium, lithium), an ammonium radical substituted or unsubstituted (methyl-, dimethyl-, trimethyl-, tetramethylammonium, dimethylpiperidinium) or derived from an alkanolamine (monoethanolamine, diethanolamine, triethanolamine).

As nonionic surfactants, mention may be made of alkyl or aryl ethers of polyalkylene oxide, polyoxyethylene sorbitan hexastearate, polyoxyethylenated sorbitan oleate and cetylstearyl and polyethylene oxide ethers. ). As the polyalkylene ether aryl ether, mention may be made of polyoxyethylenated alkylphenols. As alkyl ether of polyalkylene oxide, mention may be made of polyethylene glycol isodecyl ether and polyethylene glycol trimethylnonyl ether containing from 3 to 15 ethylene oxide units per molecule.

Mention may also be made, by way of example, of surfactants: ionic, nonionic or amphoteric fluorinated surfactants and mixtures thereof, for example:

perfluoroalkyls,

- - perfluorobetaines,

the ethoxylated polyfluoroalcohols,

ammonium polyfluoroalkyls,

surfactants whose hydrophilic part contains one or more saccharide unit (s) bearing (s) of five to six carbon atoms and whose hydrophobic part contains a unit of formula R ^f (CH ₂ ) n-, wherein n = 2 to 20 and Rf is a perfluoroalkyl unit of the formula CmF2m + 1, wherein m = 1 to 10; and

polyelectrolytes having perfluoroalkyl fatty side groups.

By fluorinated surfactant is meant, as is well known per se, a compound formed of an aliphatic perfluorocarbon moiety, comprising at least three carbon atoms, and a hydrophilic, ionic, nonionic or amphoteric moiety. The perfluorocarbon portion of at least three carbon atoms may represent either all or only a fraction of the fluorocarbon portion of the molecule. Regarding this type of compound, there is a large number of references in the literature. The skilled person can refer in particular to the following references: - FR-A-2 149 519, WO-A-94 21 233, US-A-3, 94,767, the book "Fluorinated Surfactants", Erik Kissa, Publisher Marcel Dekker Inc. (1994) Chapter 4, including Tables 4.1 and 4.4.

These include, in particular, the products sold by Du Pont under the name ZONYL ^®, eg FSO, FSN- 00, FS-300, FSD and fluorinated surfactants naming Forafac ^® distributed by the company DU PONT and the products sold under the name FLUORAD ^® by the company 3M.

These surfactants include, in particular, anionic perfluoroalkyl compounds, cationic, nonionic and amphoteric surfactants, and among them, particularly, the surfactants of the class of ZONYL ^® marketed by Du Pont, marketed by Du under the respective bridge ZONYL ^® FSA, ZONYL ^® FSO, ZONYL ^® FSC and ZONYL ^® FSK. We can further specify about them:

ZONYL ^® FSO 100: CAS 65545-80-4, (nonionic) 99 to 100%, the remainder being 1,4-dioxane,

- ZONYL ^® FSN: CAS 65545-80-4, 99 to 100%, the rest being sodium acetate and 1,4-dioxane,

- ZONYL ^® FS-300: CAS 65545-80-4, 40%, the remainder being 1,4-dioxane (<0.1%) and water

- ZONYL ^® FSD: CAS 70983-60-7 30% (cationic), the balance being hexylene glycol (0%), sodium chloride (3%) and water (57%).

We can also mention:

• perfluoroalkyl betaines (amphoteric) such as that marketed by DU PONT under the name Forafac ^® 1157 polyfluoroalcools ethoxylates (nonionic) such as that marketed by DU PONT under the name Forafac 1110 D, the ammonium salts polyfiuoroalkyl (cationic), such as that marketed by DU PONT under the name FORAFAC 179;

Surfactants whose hydrophilic part contains one or more saccharide unit (s) containing from 5 to 6 carbon atoms (units derived from sugars such as fructose, glucose, mannose, galactose, talose, gulose, allose, altose, idose, arabinose, xylose, lyxose and / or ribose) and whose hydrophobic part contains a unit of formula R ^F (CH ₂ ) _n , where n can from 2 to 20, preferably from 2 to 10 and R represents a perfluoroalkyl moiety of formula C _m F2m + i with m ranging from 1 to 10, preferably 4 to 8, chosen from those having the characteristics defined above above ; mention may be made of perfluoroalkylated fatty acid monoesters and sugars such as sucrose, the monoester function being able to be represented by the formula R ^F (CH 2) _n C (O), where n may range from 2 to 10 and R ^F represents a perfluoroalkyl unit of formula C _m F2m + i with m ranging from 4 to 8, described in Journal of the American Oil Chemists' Society (JAOCS), Vol. 69, no. 1 (January 1992) and selected from those having the characteristics defined above; and

Polyelectrolytes having fatty perfluoroalkyl side groups such as polyacrylates having R ^F (CH ₂ ) _{n groups in} which n can range from 2 to 20, preferably from 2 to 10, and R ^F represents a perfluoroalkyl unit of formula C _m F ₂ m + 1 with m possibly ranging from 1 to 10, preferably from 4 to 8, chosen from those having the characteristics defined above; polyacrylates having CH ₂ C ₇ F _{5 groups} described in J. Chim. Phys. (1996) 93, 887-898 and selected from those having the characteristics defined above.

The amount of surfactant (T) is a function of the type of each constituent present and the nature of the surfactant used. As a general rule, the emulsion comprises from 0.5 to 10% by weight of surfactant relative to the total weight of the emulsion (better still from 0.5 to 7% by weight).

The water (E) is preferably present in proportions of between 10 and 90% and preferably between 20 and 60% by weight relative to the total weight of the composition.

Furthermore, in the aqueous dispersions or in the emulsions, it is also possible to use antifoam adjuvants, biocides, rheology modifiers, coalescing agents, dispersing agents, acidifying and neutralizing agents. bases and / or thickeners.

The concentrations of such adjuvants are known to those skilled in the art.

According to another embodiment, the linear, cyclic or three-dimensional polyorganosiloxane (B) and as defined above can be used in a proportion of 0.01 to 10% by weight, and preferably from 0.01 to 5% by weight. % by weight and more preferably from 0.01 to 2% by weight relative to the total weight of the composition (A).

A second subject of the present invention relates to hydrophobized and lubricated vegetable fibers that can be obtained by the process as described above.

A third object of the present invention relates to the use of hydrophobized and lubricated plant fibers according to the invention for the manufacture of an insulating material.

The methods of applying the treatments are well known to those skilled in the art. We can particularly mention soaking, padding, spraying. By dipping, the fibers are dipped in a tray filled with the silicone composition, dewatered and then dried.

The padding application involves immersing the fibers in a tray filled with the silicone-based composition and squeezing them between two rolls held against each other by a measured pressure. This technique makes it possible to deposit a determined quantity of silicone. Drying is carried out continuously following padding at temperatures between 120 ° and 160 ° C. The immersion can be done in an aqueous medium or solvent.

The impregnation by spraying can be carried out in several passages to better penetrate the heart of the plant fibers.

They are conventionally followed by a drying step which can be natural at ambient temperature or forced at temperature. In the case of fast drying, it is advisable not to exceed 160 ° C.

A final object of the present invention is to propose new insulating materials comprising the hydrophobized and lubricated vegetable fibers according to the invention.

The following examples which illustrate the invention demonstrate the excellent water-repellent and softening properties of the plant fibers treated according to the method of the invention.

EXAMPLES

1) Raw materials used

BLUESIL ™ FLD 47V350 sold by Bluestar Silicones: non-reactive polydimethylsiloxane oil (PDMS), viscosity approximately 350 mm ² / s at 25 ° C.

BLUESIL ™ WR 68 sold by Bluestar Silicones: Methyl hydrogen reactive polysiloxane (SiH) oil, viscosity approximately 25 mm ² / s at 25 ° C.

Epoxy-functional silicone oil (SiEpoxy) with about 0.09 mole of epoxy for

100 g of oil and a viscosity of approximately 300 mm ² / s at 25 ° C.

(B1): polydimethylsiloxane comprising M units bearing an ethoxy function and at least one D unit carrying a function - (CH ₂ ) 3 -NH ₂ , with 0.2% nitrogen by weight relative to the weight oil and a viscosity of approximately 300 mm ² / s at 25 ° C.

(B2): polydimethylsiloxane comprising M units bearing a methoxy function and at least one T unit carrying a function - (CH ₂ ) 3 -NH- (CH ₂ ) 2 -NH ₂ .with 0.22% d nitrogen by weight relative to the weight of the oil and a viscosity of approximately 2500 mPa.s at 25 ° C.

DYNASILAN ^R AMEO sold by Evonik: 3 Amino propyl triethoxysilane

SILQUEST ^R VS142 sold by Momentive: aminoalkyl silane in solution in water

2) Procedure for the preparation of silicone dispersions

(51) 0.3g of BLUESIL FLD 47V350 are dispersed in 100g of white spirit.

(52) 0.3g of BLUESIL WR 68 are dispersed in 100g of white spirit.

(53) 0.3g of (SiEpoxy) are dispersed in 100g of white spirit.

(54) 0.3g of silicone oil (B1) are dispersed in 100g of white spirit.

(55) 0.3g of silicone oil (B2) are dispersed in 100g of white spirit.

(56) 0.3g of Dynasilan AMEO are dispersed in 00g of white spirit.

3) Procedure for the preparation of silicone emulsions in water

The emulsions are prepared as follows:

In an IKA ^® reactor, a portion of the water, a nonionic surfactant are mixed. Then, the mixture (s) to be emulsified with stirring is added to this mixture so as to obtain an oil-in-water emulsion; and

at the end of the introduction of the constituent (s) and after homogenization, the final dilution of the emulsion and additions of any additives (acid, base, biocides, etc.) are carried out

Emulsions (ED (E2) and (E3)

(E1) Emulsion 1 (PDMS): consisting of 56% by weight of a non-reactive poly (dimethyl) siloxane oil Bluesil 47V350. (E2) Emulsion 2 (SiH): consisting of 50% by weight of a BLUESIL WR 68 reactive hydrogen polysiloxane methyl ester oil.

(E3) Emulsion 3 (amino silicone): consisting of 51% by weight of a silicone oil (B2).

4) Treatment of plant fibers:

- Treatment of vegetable fibers in solvent phase

2 g of plant fibers are immersed in a dispersion of silicone in the solvent phase (S1 to S6) and mixed for 1 minute.

The plant fibers are then dewatered until the solution no longer dries (final mass = 6.5g) and then dried at room temperature 48h before carrying out the lubrication (softening) and hydrophobicity tests.

- Treatment of vegetable fibers in aqueous phase

2g of dry vegetable fibers are immersed in water and wrung out (until mass drained = 5x dry mass, ie 10g) to be in the industrial conditions.

The 10 g of wet plant fibers are immersed in an aqueous silicone solution containing 0.4 g of silicone emulsion in water (E1 to E3) in 100 ml of water and mixed for 1 minute.

The vegetable fibers are then dewatered until the emulsion no longer dries (final mass = approximately 12g), and then dried at room temperature for 48 hours before carrying out the lubrication (softening) and hydrophobicity tests.

5) Tests

Hydrofugation test = flotation (figure in appendix):

1 gram of fiber (treated or not) is deposited on water (in a 250 ml bottle filled to 100 ml) and the behavior of these fibers is observed over time (immediately, then after 24h, 48h and 3 days) .

If the fibers flow: (see figure 1a): they are not waterproofed then "no" is entered in the table of results.

If the fibers do not flow (see Figure 1 b): they are water repellent so "yes" is entered in the results table.

Water recovery test

40g of dry vegetable fibers are immersed in water and wrung out.

350 g of wet plant fibers are obtained which are then treated by immersion in a silicone emulsion solution (E3) diluted with 0.3% silicone. After 1 minute of immersion, the fibers are dewatered and a small slab of fibers 6.5cm diameter and 2cm thick is formed. After drying in an ambient atmosphere until constant mass, ie after about 3 days, a test of water uptake is carried out. The cakes of treated and untreated fibers are deposited on the surface of a tank (length 40 cm - width 30 cm - height 6 cm) filled at mid-water level and the quantity of water absorbed after 2 hours and 24 hours is determined by weighing. , expressed in kg / m ² .

Lubrication test = softening:

It is determined by the touch, the softness and the slipperiness of the fibers compared to untreated fibers which allows to classify the fibers relative to the untreated control.

In the absence of effect, the sign "=" is mentioned in the table of results.

If there is deterioration of the touch, it is mentioned in the results table.

If there is a softening a sign "+" or even "++" is entered in the table of results.

Results:

Table 1: Wood Fibers - Solvent Medium (White spirit)

ND = not determined Table 2: Hemp fibers - Solvent medium (White spirit)

In a solvent medium, with respect to the vegetable fibers of untreated wood or hemp (controls), only the plant fibers of wood or hemp placed in contact with a composition containing a polyorganosiloxane (B) (Examples 1 to 3) are at the water-repellent and lubricated (softening)

Vegetable fibers treated with a PDMS oil (Comparative Nos. 1 and 4) are neither water-repellent nor lubricated.

Vegetable fibers treated with a polyorganosiloxane oil with SiH functions (Comparative Nos. 2 and 5) or epoxy functions (Comparative No. 6) are not water-repellent.

Vegetable fibers treated with an amino silane (Comparative Nos. 3 and 7) have their touch degraded. Table 3: Wood Fibers - Aqueous Media

ND = not determined

In aqueous medium, compared to untreated vegetable fibers (control), only vegetable fibers put in contact with a silicone emulsion in water of a

Polyorganosiloxane (B) (E3), Example 4 according to the invention, are both water-repellent and lubricated (softening).

Vegetable fibers treated with a PDMS (E1) oil emulsion (Comparative No. 8) are neither water-repellent nor lubricated.

Plant fibers treated with an SiH (E2) functional polyorganosiloxane oil emulsion (Comparative No. 9) are not water-repellent.

The vegetable fibers treated with an aqueous silane amine solution (Comparative No. 10) are not water-repellent and are slightly slightly lubricated.

Table 4: Water Return

Wood fiber Water recovery (Kg / m ² )

(Length between 0.1 and 30 mm) After 2 hours After 24 hours

Untreated wood fibers (control) 17 20

Fibers treated with E3

0.5 1, 5

(Example 5 according to the invention) Vegetable fibers treated with an aqueous emulsion of a polyorganosiloxane (B) (E3), Example 5 according to the invention, have a very low water recovery compared to the control (untreated fibers) and this after 2 and 24 hours.

The invention is not limited to the examples described and shown, since various modifications can be made without departing from its scope.

Claims

1. Process for hydrophobing and lubricating plant fibers containing respectively 40 to 80% by weight of cellulose, 10 to 30% by weight of hemicellulose and 0.1 to 30% by weight of lignin, expressed as a percentage by weight of fibers, characterized in that said plant fibers are brought into contact with at least one composition (A) comprising at least one linear, cyclic or three-dimensional polyorganosiloxane (B) consisting of the following units.

wherein:

the symbols R ¹ , R ² and R ³ , which are identical and / or different, represent a monovalent hydrocarbon radical chosen from linear or branched alkyl radicals having from 1 to 4 carbon atoms, the linear or branched aikoxy radicals having from 1 to 4 carbon atoms, a phenyl radical and, preferably, a hydroxyl radical, an ethoxy radical, a methoxy radical or a methyl radical;

the symbols Z, identical or different, represent R ¹ and / or V;

-R ⁴ -N (R ⁵ ) (R ⁶ ) (I)

in which:

the symbol R ⁶ being a hydrogen atom or a radical of formula (II) below:

- [R ⁷ -N (R ⁸ )] _to R ⁸

in which:

the symbol R ⁷ being a divalent radical of formula (III) below:

- [C (R ⁸ ) (R ⁸ ) -] _b

- 0 <a <40

- b = 1, 2 or 3, the symbol R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having from 1 to 40 carbon atoms;

- 10 <x <2000,

- 0 <y <50,

- 0 <w <8, and

with the additional provisos that at least one of Z represents V and that the composition contains neither free fatty acid nor polyorganosiloxane with a beta carboxy function.

2. Process for hydrophobing and lubricating plant fibers according to claim 1, characterized in that said plant fibers have a length of between 0.1 and 300 mm.

3. Process for hydrophobing and lubricating plant fibers according to claim 1 or 2, characterized in that said plant fibers are respectively composed of 50 to 80% cellulose, 10 to 25% hemicellulose and 0.01 at 10% lignin, expressed as a percentage by weight of fibers.

4. Process for hydrophobing and lubricating plant fibers according to claim 1 or 2 or 3, characterized in that the composition (A) comprises:

at least one dispersing medium, and

at least one linear, cyclic or three-dimensional polyorganosiloxane (B) as described according to the claim.

5. Process for hydrophobing and lubricating plant fibers, according to claim 1 or 4, characterized in that the composition (A) is in the form of an aqueous dispersion of silicone.

6. Process for hydrophobing and lubricating plant fibers, according to claim 1 or 4, characterized in that the composition (A) is in the form of a silicone emulsion in water.

7. Process for hydrophobing and lubricating plant fibers according to any one of claims 1, 4, 5 or 6, characterized in that the composition (A) contains from 0.01 to 0% by weight of linear polyorganosiloxane , cyclic or three-dimensional (B).

8. Process for hydrophobing and lubricating plant fibers, according to any one of claims 1, 4, 5 or 6, characterized in that the composition (A) contains from 0.01 to 5% by weight of linear polyorganosiloxane , cyclic or three-dimensional (B).

9. Process for hydrophobing and lubricating plant fibers, according to claim 1, 4, 5 or 6, characterized in that the composition (A) contains from 0.01 to 2% by weight of linear polyorganosiloxane, cyclic or three-dimensional (B).

10. Water-repellent and lubricated vegetable fibers obtainable by the process as described according to any one of claims 1 to 9.

11. Use of water-repellent and lubricated vegetable fibers as described in claim 10 for the manufacture of an insulating material.

12. Material based on vegetable fibers water-repellent and lubricated as described in claim 10.