EP1858966A1

EP1858966A1 - Composition comprising a thermoplastic polymer and a hydrophilizing agent

Info

Publication number: EP1858966A1
Application number: EP06726017A
Authority: EP
Inventors: Daniel Joubert; Marc Balastre; Antoine Guiu
Original assignee: Rhodia Recherche et Technologies SAS
Current assignee: Rhodia Recherche et Technologies SAS
Priority date: 2005-03-14
Filing date: 2006-03-03
Publication date: 2007-11-28
Also published as: WO2006097597A1; US20090105679A1; US8287509B2; JP2012107251A; JP2008535955A

Abstract

The invention concerns a method for preparing thermoplastics to obtain a hydrophilic behaviour of the surface of objects made from said thermoplastics. The invention also concerns the additives used to obtain said surface hydrophily, said additives being mixed and jointly melted with the thermoplastics (mass-additivation process). The melted mixtures of thermoplastics and additives are shaped by any conventional means (extrusion, injection, film stretching) to obtain the desired objects. The invention further concerns the uses of said thermoplastic objects with hydrophilized surfaces.

Description

COMPOSITION COMPRISING A THERMOPLASTIC POLYMER AND A HYDROPHILIZATION AGENT

The invention relates to a process for the preparation of thermoplastic polymers which makes it possible to obtain a hydrophilic behavior of the surface of objects manufactured with these thermoplastic polymers.

It also relates to the additives used to obtain this surface hydrophilicity, said additives being mixed and co-melted with the thermoplastics (additive in the mass).

The melt blends of the thermoplastic polymers and additives are shaped by any conventional means (extrusion, injection, printing films ...) to obtain the desired objects. The invention finally relates to the applications of these objects in thermoplastic polymers with hydrophilized surfaces.

Plastics such as polyesters, polyamides, polyolefins, and more particularly polypropylene normally have very hydrophobic surfaces, which is a drawback for many applications of objects made from these thermoplastics. For example, sails or films, porous or discontinuous, made from polypropylene or polyester yarns or fibers, obtained by the so-called nonwoven technique, which we will call under the generic term "non-woven textile surface" have an essentially hydrophobic surface behavior. This behavior requires that they be superficially coated, in post-treatment, with soluble surfactant compositions, to be used in applications such as hygiene, wiping, diapers ....

This surface treatment has the disadvantage of not being durable and also of allowing the surfactant used in the treatment layer to dissolve in the water in contact with it. This point is particularly to be avoided in hygiene applications like diapers.

Also the hydrophilization of the surface of objects is sought in other applications for example those for mass objects such as parts for the automotive industry. It is desired to be able to paint these parts, and plastics such as polypropylene are not suitable for painting. In this case, the surface treatment with a coating of a hydrophilic or amphiphilic species is not a viable solution because the hydrophilizing treatment is neither durable nor adherent. In another type of application, hydrophilicity is sought because it would clean the water in question. In particular food containers polyolefin (PE, PP) pose a cleaning problem when you want to wash in an automatic dishwasher. While all the glass or ceramic utensils are clean and dry from the dishwasher, the polyolefin utensils are still wet, with non-spreading drops of water, because of the great hydrophobicity of the utensils and containers concerned.

Finally the hydrophilicity of polypropylene packaging or films is also sought to prevent slugging, dust deposition, fogging, during the storage of products wrapped polypropylene films in the departments of sales. At this level, hydrophilicity contributes to the non-adhesion of dust or greasy soils, but also to the flow of static electricity charges responsible for certain types of ensalissement.

The need existed to find a way to prepare a thermoplastic polymer that has a more hydrophilic surface.

One of the aims of the present invention is therefore to find a means of preparing a thermoplastic polymer which has a more hydrophilic surface.

This object, and others, is achieved by the present invention which therefore relates to a composition comprising a thermoplastic polymer and hydrophilizing agent selected from anionic surfactants in the form of salts or in acid form.

It also relates to a process for preparing the thermoplastic polymer in which the hydrophilizing agent has been incorporated.

The invention finally relates to the applications of this thermoplastic polymer with hydrophilized surface. By thermoplastic polymer is meant polyesters, polyamides, polyolefins such as polyethylene and polypropylene.

By anionic surfactants in the form of salts or in acid form, mention may be made of:

alkylsulphonic acids, arylsulphonic acids, optionally substituted with one or more hydrocarbon groups, and whose acidic function is partially or totally salified, such as C ₈ -C ₅₀ , especially C ₈ -C ₃₀ , alkylsulphonic acids, preferably C ₂₂ -C _θ, benzenesulfonic acid, naphthalenesulfonic acids substituted by one to three alkyl groups C ₁ -C _30, preferably C ₄ -C ₁₆ alkyl and / or alkenyl C ₂ -C _30, preferably C ₄ -C _1B -

the mono- or diesters of alkylsulfosuccinic acids, of which the linear or branched alkyl part, optionally substituted with one or more hydroxylated and / or alkoxylated, linear or branched C ₂ -C ₄ (preferably ethoxylated, propoxylated, ethopropoxylated) groups; ). the phosphate esters chosen more particularly from those comprising at least one saturated, unsaturated or aromatic hydrocarbon group, linear or branched, comprising 8 to 40 carbon atoms, preferably 10 to 30, optionally substituted by at least one alkoxylated (ethoxylated) group, propoxylated, ethopropoxylated). In addition, they comprise at least one phosphate ester group, mono- or diesterified so that one or two free acid groups or partially or totally salified. The preferred phosphate esters are of the mono- and diester type of phosphoric acid and of alkoxylated (ethoxylated and / or propoxylated) mono-, di- or tristyrylphenol, or of alkoxylated (ethoxylated) mono-, di- or trialkylphenol and / or propoxylated), optionally substituted with one to four alkyl groups; phosphoric acid and a C ₈ -C ₃₀ alcohol, preferably C ₁₀ -C ₂₂ alkoxylated (ethoxylated or ethopropoxylated); phosphoric acid and a C ₈ -C ₂₂ alcohol, preferably C ₁₀ -C ₂₂ , non-alkoxylated.

sulphate esters obtained from saturated or aromatic alcohols, optionally substituted with one or more alkoxylated groups (ethoxylated, propoxylated, ethopropoxylated), and for which the sulphate functional groups are in the free acid form, or partially or completely neutralized . By way of example, mention may be made of sulfate esters obtained more particularly from saturated or unsaturated C ₈ -C ₂₀ alcohols, which may comprise 1 to 8 alkoxylated units (ethoxylated, propoxylated, ethopropoxylated); sulphate esters obtained from polyalkoxylated phenol, substituted with 1 to 3 saturated or unsaturated C ₂ -C ₃₀ hydroxycarbon groups, and in which the number of alkoxylated units is between 2 and 40; sulphate esters obtained from polyalkoxylated mono-, di- or tristyrylphenol in which the number of alkoxylated units ranges from 2 to 40. The anionic surfactants may be in acid form (they are potentially anionic), or in a form partially or totally salified, with a counter-ion. The counterion may be an alkali metal, such as sodium or potassium, an alkaline earth metal, such as calcium, or an ammonium ion of formula N (R) ₄ ⁺ in which R, which may be identical or different, represent a hydrogen atom or a C ₁ -C ₄ alkyl radical optionally substituted with an oxygen atom. The anionic surfactants are preferably used in the form of sodium salts. Even more preferably, the anionic surfactant is sodium alkysulphonate, the alkyl group of which is linear or branched, comprising on average from 6 to 30 carbon atoms. The anionic surfactant has, for example, the following formula: CH ₃ - (CH ₂ ) _π -CH ₂ -SO ₃ Na wherein n is an average number of between 8 and 16.

A product that can be used is an anionic product sold by Rhodia under the name Catafor FL or Catafor AFL, in solid form. The amount of hydrophilizing agent introduced into the polymer is such that the weight ratio between the hydrophilizing agent and the thermoplastic polymer is between 1/99 and 10/90.

The hydrophilizing agent is mixed and co-melted with the thermoplastic polymer. The thermoplastic polymer is generally in the form of solid granules.

The hydrophilizing agent can be mixed at room temperature with the polymer granules and then introduced into a mixing tool heated.

The hydrophilizing agent may also be introduced into the mixing tool in which the polymer in the molten state is already present. The temperature mixing tool may be a vessel provided with rotors and heated by a fluid circulation. This is called an internal mixer. It is a "batch" process.

For example, a Brabender mixer may be mentioned. After cooling, a blank of solid material is recovered which can be shaped in a mold by compression. The temperature mixing tool may also be an extruder in which the material is transported, heated and kneaded by rotating screw members. It is a "continuous" process. For example, a Werner ZSK30 extruder may be mentioned. A rush of molten material is recovered which is cooled and then cut to obtain granules. These granules can then be injected in the form of test pieces or finished materials.

When the hydrophilizing agent is in solid form, that is to say in the form of a powder, flake or granules, the incorporation is then easily as indicated above. When the hydrophilizing agent is in liquid form, 100% hydrophilizing agent, or the hydrophilizing agent in solution in a solvent, there are several possibilities of incorporation.

It is possible to carry out a direct incorporation of liquid, with or without evaporation of the following solvent if the boiling temperature of the liquid (hydrophilizing agent or solvent) is below or above the transformation temperature (around

18O ⁰ C).

It is also possible to impregnate this liquid on a porous support, such as for example a precipitated silica to obtain a powder. This powder can then be shaped to facilitate its use. For example, reference may be made to FR 2,843,122, which discloses means for incorporating liquids into thermoplastic polymers.

The present invention therefore also relates to a process for preparing a composition comprising the thermoplastic polymer and the hydrophilizing agent, characterized in that the hydrophilizing agent is mixed with the thermoplastic polymer in molten form.

The present invention therefore also relates to a process for preparing a composition comprising the thermoplastic polymer and the hydrophilizing agent, characterized in that the hydrophilizing agent is mixed with the thermoplastic polymer optionally with other ingredients, for example fillers or stabilizers, by mixing with the thermoplastic polymer before melting, by direct introduction into the molten thermoplastic polymer, and / or by masterbatch. The melt blends of thermoplastic polymer and hydrophilizing agent can be shaped by any conventional means (extrusion, injection, pulling films ...) to obtain the desired objects.

The melt blends of thermoplastic polymer and hydrophilizing agent can thus be formed into molding powder, in the form of an extruded and / or blown and / or injected object, in the form of a film, or in the form of fibers. yarns or filaments, optionally assembled in woven or nonwoven textile surface.

The invention also relates to the applications of these objects in thermoplastic polymers with hydrophilized surfaces.

As examples of objects made of thermoplastic polymer with a hydrophilized surface, mention may in particular be made of a nonwoven textile surface comprising fibers based on a composition according to the invention.

In particular, a nonwoven textile surface comprising fibers based on a composition according to the invention in which the thermoplastic polymer is based on polypropylene may be mentioned. This textile surface can be used in the manufacture of baby diaper, feminine hygiene product or adult incontinence care product. Examples of objects made of thermoplastic polymer with a hydrophilized surface include mass objects such as parts for the automotive industry. Examples of objects made of thermoplastic polymer with a hydrophilized surface include food containers made of polyolefin (polyethylene or polypropylene).

Examples of objects made of thermoplastic polymer with a hydrophilized surface include packaging or polypropylene films.

The invention finally relates to a use of anionic surfactants in the form of salts or in acid form as defined above as hydrophilizing agent of a composition comprising a thermoplastic polymer.

Surface hydrophilicity is evaluated by measuring the contact angle between a drop of purified, distilled water and said surface. A drop of distilled water of calibrated size is deposited under standardized and repetitive conditions on the surface to be to study. It spreads or retracts more or less depending on the hydrophilicity of the surface, and with suitable equipment, it is possible to measure the angle formed by the deposited drop and the surface.

The apparatus used may be, for example, a goniometer for measuring the wetting angle, for example of the Tantec mark. It is also possible to use an automatic measuring device, such as the IT Concept company's droplet monitor with optical bench. This is the case of the measurements that have been made in the examples presented below. The manipulation consists in depositing on the clean and smooth surface of the sample a drop of water of calibrated volume equal to two microliters using a syringe. The drop is illuminated by a uniform light source, type integrating sphere, the image of his profile is projected by a telecentric telephoto lens on a CCD camera. It is digitized and then processed by software to determine several times per second the right and left contact angles defined as the angles between the plane formed by the support and tangent planes on either side of the base of the drop.

Typically, pure polypropylene has a contact angle with pure water of 105 °. The hydrophilizing agents when they are mixed with the thermoplastic polypropylene polymer make it possible to lower this value very substantially, at levels between 70 and 85 °. Other aspects and advantages of the products which are the subject of the invention will emerge in the light of the examples which are presented below by way of illustration and in no way limitative.

Unless otherwise indicated, all percentages given in this application are percentages by weight.

Example 1 -Implementation of these products

The constituents (94.9% of isotactic polypropylene homopolymer polypropylene polymer sold by ATOFINA under the name PPH4060, 5% of hydrophilizing additive and 0.1% of Irganox B225 thermal stabilizer) are introduced into the tank of a mixer. internal brand "Brabender" brought to a temperature of 15O ⁰ C.

The tank is equipped with two counter-rotating rotors of thermoplastic type W50, rotating at a speed of rotation of 125 RPM. Given the internal shear, the final temperature of the mixture is between 18O ⁰ C and 190 ⁰ C. After a mixing time of 5 minutes, a charged polymer blank is extracted from the tank, and is pressed into a mold 800 microns thick, between two compression plates heated to 200 ⁰ C under 200 bar pressure for 2 minutes. The mold is then cooled between two trays cooled to 18 ⁰ C under a pressure of 200 bar for 4 minutes. After cooling and consolidation, these specimens are subjected to various physico-chemical tests to check the hydrophilicity of their surface and the resulting properties.

Remarks on the implementation and effect of additives on the melted mixtures:

There are different physical effects during mixing in the Brabender kneader, which can provide significant benefits in this preparatory phase. For the Catafor FL (or "AFL"), there is a lubricating effect. The finished product (test specimen) has a modified feel, described as "soft" or soft.

Example 2 - Hydrophilizing Effects

They are given (via the measurement of the contact angle with distilled water) in the following Table I, and according to the aging of the specimens in the open air.

The measurements were made in the examples presented below using a drop tensiometer with optical bench called the SDT 200 from the company IT Concept. The manipulation consists in depositing on the clean and smooth surface of the sample a drop of water of calibrated volume equal to two microliters using a syringe. The drop is illuminated by a uniform light source, type integrating sphere, the image of his profile is projected by a telecentric telephoto lens on a CCD camera. It is digitized and then processed by software to determine several times per second the right and left contact angles defined as the angles between the plane formed by the support and tangent planes on either side of the base of the drop. The result shown in Table I corresponds to the average of 10 to 15 measurements.

Table I

PP means polypropylene The surface of the test pieces is cleaned with ethanol prior to depositing the drop for the measurement of the contact angle. It is found that the hydrophilicity of the surface is well obtained durably.

Claims

A composition comprising a thermoplastic polymer and a hydrophilizing agent selected from anionic surfactants in the form of salts or in acid form; preferably in the form of sodium salts.

2. Composition according to claim 1, characterized in that the anionic surfactant is a sodium alkysulphonate, the alkyl group is linear or branched, comprising on average from 6 to 30 carbon atoms.

3. Composition according to one of the preceding claims, characterized in that the anionic surfactant has the following formula:

CH ₃ - (CH ₂ ) _H -CH ₂ -SO ₃ Na wherein n is an average number of between 8 and 16.

4. Composition according to one of the preceding claims, characterized in that the thermoplastic polymer is selected from polyesters, polyamides, or polyolefins such as polyethylene and polypropylene.

5. Composition according to one of the preceding claims, characterized in that the thermoplastic polymer is based on polypropylene.

6. Composition according to one of the preceding claims, characterized in that it is under powder of molding powder, in the form of an extruded object and / or blown and / or injected, in the form of a film, or under fiber form son or filaments, optionally assembled in woven or nonwoven fabric surface.

7. Composition according to one of the preceding claims, characterized in that the weight ratio between the hydrophilizing agent and the thermoplastic polymer is between 1/99 and 10/90.

8. Process for preparing a composition according to one of the preceding claims, characterized in that the hydrophilizing agent is mixed with the thermoplastic polymer in molten form.

9. Method according to the preceding claim, characterized in that the hydrophilizing agent is mixed with the thermoplastic polymer optionally with other ingredients, for example fillers or stabilizers, by mixing with the thermoplastic polymer before melting, by direct introduction into the molten thermoplastic polymer, and / or by masterbatch.

10. A nonwoven textile surface comprising fibers based on the composition according to one of the preceding claims, wherein the thermoplastic polymer is based on polypropylene.

11. Textile surface according to the preceding claim, included in a baby diaper, a feminine hygiene product or a product for the care of adult incontinence.

12. Use of anionic surfactants in the form of salts or in acid form according to any one of claims 1 to 3 as hydrophilizing agent of a composition comprising a thermoplastic polymer.