(19)
(11)EP 2 698 421 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
26.02.2020 Bulletin 2020/09

(21)Application number: 12180569.1

(22)Date of filing:  15.08.2012
(51)International Patent Classification (IPC): 
C10M 173/02(2006.01)
C10N 40/00(2006.01)
C10N 30/06(2006.01)

(54)

A water-based lubricant

Schmiermittel auf Wasserbasis

Lubrifiant à base d'eau


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
19.02.2014 Bulletin 2014/08

(73)Proprietor: Sika Technology AG
6340 Baar (CH)

(72)Inventor:
  • Salo, Kai
    02340 Espoo (FI)

(74)Representative: Sika Patent Attorneys 
c/o Sika Technology AG Corp. IP Dept. Tüffenwies 16 Postfach
8048 Zürich
8048 Zürich (CH)


(56)References cited: : 
EP-A1- 2 423 246
GB-A- 1 563 789
US-A1- 2004 053 792
WO-A1-2013/160101
US-A1- 2004 053 790
US-A1- 2010 225 026
  
  • DATABASE WPI Week 198119 Thomson Scientific, London, GB; AN 1981-33254D XP002687447, & JP 56 026994 A (TACHIBANA SHOKAI KK) 16 March 1981 (1981-03-16)
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description


[0001] The present invention is directed at a water-based lubricant which is preferably free of oils. The water-based lubricant according to the present invention comprises water, at least one organic polymer and at least one polyhydric alcohol.

[0002] Today, many applications involving moving or rotating objects require lubricants to prevent the work-pieces and tools from overheating and excessive wear. The state of the art in lubricants today are mineral oil based lubricants, however, these have suffered from recent drawbacks as oil is extracted from non-renewable resources and the prices of oil have been on the rise for a considerable time. Moreover, mineral oils have further disadvantages that their heat capacity is relatively low, so that the efficiency in dissipating heat away from a work-piece is low as well. Further disadvantages of conventional oil based lubricants are that they are usually harmful to the health of the user and flammable. This requires technical efforts for occupational safety, fire-safety and disposal. Moreover, oil based lubricants have proven difficult to remove from soiled workers clothes.

[0003] GB1563789 teaches an aqueous lubricant composition, the lubricant comprising at least one alkali metal salt of at least one aliphatic monocarboxylic acid, an at least partially water-soluble bactericide, and water. Such lubricant compositions can be used for the assembly of push-fit pipes.

[0004] There is still a need for alternative lubricants which are based on materials with a high heat capacity to improve the ability of the lubricant for dissipating heat away from a work-piece. In addition, there is a need for lubricants which are based on easily accessible base materials and which have a low flammability to improve worker safety. Finally, there is a need for lubricants that are easy to manufacture and handle, and easy to wash off from cloth, equipment, floors, skins, etc. The present application addresses these needs.

Summary of the invention



[0005] The present invention is directed at a water-based lubricant comprising water, at least one organic polymer and at least one polyhydric alcohol.

[0006] In a preferred embodiment of the present application, the water-based lubricant comprises less than about 1 wt.-% oil, more preferably less than about 0.5 wt.-% oil, even more preferably less than about 0.1 wt.-% oil and most preferably is essentially free of oil.

[0007] "Oil", as this expression is used in the context of the present invention, encompasses mineral oils as well as synthetic oils. These oils primarily comprise hydrocarbon components, in particular linear or branched alkanes. Mineral oils include white oils, liquid paraffin and liquid petroleum. Synthetic oils are e.g. alkanes obtainable by a Fischer-Tropsch process.

[0008] The organic polymer in the water-based lubricant is preferably a synthetic polymer. The organic polymer is a polycarboxylate and a polyacrylic acid. In a preferred embodiment of the present application, the organic polymer may also comprise natural organic polymers such as starches, celluloses, alginates, etc. In another embodiment, it is preferred that the water-based lubricant is essentially free of non-modified natural organic polymers.

[0009] Non-modified in the context of this application means, that the natural polymer is not chemically modified such as for example by alkylation, crosslinking, etc.

[0010] The content of the organic polymer in the water-based lubricant preferably is in the range of about 5 to 20 wt.-% and more preferably about 7 to 15 wt.-%, based on the total weight of the water-based lubricant.

[0011] The composition may also comprise a base in a concentration sufficient to adjust the pH of the lubricant to the desired range. A preferred base for use in the water-based lubricant according to the present invention is an alkali or earth alkali hydroxide, most preferably sodium or potassium hydroxide.

[0012] The polyhydric alcohol for use in the water-based lubricant according to the present application is preferably a dihydric alcohol, and more preferably an alkylene diol, most preferably propylene glycol. Mixtures of two or more polyhydric alcohols may also be used. The polyhydric alcohol may be included into the water-based lubricant according to the present application with a content of preferably from about 10 to 35 wt.-%, more preferably about 15 to 30 wt.-%, and even more preferably about 20 to 25 wt.-%, based on the total weight of the water-based lubricant.

[0013] The water-content of the water-based lubricant according to the present application is preferably in the range of from about 20 to 75 wt.-%, more preferably about 40 to 70 wt.-%, and most preferably about 55 to 65 wt.-%, based on the total weight of the water-based lubricant.

[0014] In addition to water, at least one polyhydric alcohol and the at least one organic polymer, the water-based lubricant may further comprise one or more additives selected from stabilizers, surfactants, defoamers, preservatives, colloidal silica, corrosion inhibitors, pigments, fragrances and soaps.

[0015] A preferred stabilizer for use in the practice of the present invention is a synthetically modified natural polymer. A particular preferred synthetically modified natural polymer for use in the present application is an alkoxylated cellulose, preferably hydroxy ethyl cellulose. Hydroxy ethyl cellulose is for example commercially available as Natrosol® 250 from Ashland Speciality Ingredients. If the water-based lubricant contains an alkoxylated cellulose, this is preferably included in an amount of from about 1 to 5 wt.-%, preferably in an amount of from about 2 to 4.5, and in particular about 2.5 to 3.5 wt.-%, based on the total weight of the water-based lubricant.

[0016] A preferred defoamer is a defoamer based on fatty acids. Such defoamer is for example commercially available as Pronal 754S from Sika.

[0017] A preferred soap for use in the practice of the present application is mustikka bliw.

[0018] Colloidal silica may be incorporated into the water-based lubricant according to the present application in an amount of from about 0.5 to 5 wt.-%, preferably, in an amount of from about 1 to 3 wt.-%, and in particular in an amount of from about 1.2 to 2.5 wt.-% based on the total weight of the water-based lubricant. Colloidal silica is for example available under the trade name Sika Stabilizer-100® from Sika.

[0019] A preferred preservative for use in the practice of the present application is phenyl methoxy methanol which is available for example as Preventol D2 from Priechel GmbH.

[0020] In the practice of the present application, it is preferred that the combined amounts of defoamers, preservatives, soaps and surfactants do not exceed about 5 wt.%, preferably the amount is equal or less than about 3 wt.-%.

[0021] In a particular preferred embodiment of the present application the water-based lubricant comprises about 55 to 65 wt.-% water, about 7 to 15 wt.-% of at least one organic polymer and about 20 to 28 wt.-% of at least one polyhydric alcohol in addition to colloidal silica, a defoamer, a stabilizer, a preservative and a surfactant.

[0022] The present application is further directed to a method of preparing a water-based lubricant as described above, which comprises a step of mixing water with at least one organic polymer and at least one polyhydric alcohol to obtain a lubricant. Also in this method it is preferred that during the preparation of the lubricant less than about 1 wt.-%, preferably less than about 0.5 wt.-%, and even more preferably, less than about 0.1 wt.-% of an oil is added to the composition.

[0023] A further embodiment of the present application is directed at the use of a lubricant as described above, for the fitting together of concrete pipes. In such applications, it is preferred, that the water-based lubricant replaces at least a fraction of a regular mineral oil-based lubricant, preferably at least about 50% of said lubricant, more preferably at least about 80% of said lubricant and most preferably replaces essentially all of the conventional oil-based lubricant.

[0024] The water-based lubricants according to the present application are advantageous over conventional mineral oil-based lubricants as described above, in that they are environmentally friendly by reducing the amount of oils needed. In addition, the lubricant requires the addition of less components which are based on conventional mineral oils resulting in significant cost-benefits with regard to oil-based lubricants. As a further benefit, the lubricants are easy to manufacture and handle, and easy to wash off from cloth, equipment, floor, skins which have been stained with the lubricants. Finally, the water-based lubricants are frost resistant down to -15 °C.

[0025] In the following, the water-based lubricant will be illustrated by way of examples, which however should not be considered as limiting in any way to the scope of the present application.

Examples:



[0026] Two water-based lubricants are prepared by mixing the ingredients indicated in Table 1.
Table 1:
ComponentAmount 
Polycarboxylate 7.65% 10.0%
Propylene glycol 23% 23%
NaOH liquid 10% 5.1% 4.6%
Hydroxy ethyl cellulose 3.4% 2.5%
Colloidal silica 3.1% 2.25%
Sika Pump* 10.6% 7.80%
Defoamer 0.08% 0.06%
Preservative 0.07% 0.05%
Soap 0.1% 0.08%
Water the remainder up to 100% the remainder up to 100%
*Sika Pump is a mix of 80-90% water, 1-5% Glycerin and long polymers.



Claims

1. A water-based lubricant comprising from 20 to 75 wt.-% water, 5 to 20 wt.-% of at least one organic polymer, 10 to 35 wt.-% of the at least one polyhydric alcohol and less than 1 wt.-% of an oil, wherein the organic polymer is a synthetic polymer in the form of a polycarboxylate which is a polyacrylic acid.
 
2. The water-based lubricant according to claim 1, wherein the lubricant comprises less than 0.5 wt.-%, more preferably less than 0.1 wt.-% of an oil.
 
3. The water-based lubricant according to any of the preceding claims, wherein the polyhydric alcohol is propylene glycol.
 
4. The water-based lubricant according to any of the preceding claims further comprising a stabilizer, preferably an alkoxylated cellulose.
 
5. The water-based lubricant according to any of the preceding claims, further comprising at least one additive selected from colloidal silica.
 
6. A method for preparing a water-based lubricant according to any one of claims 1 to 5, comprising mixing water with at least one organic polymer and at least one polyhydric alcohol to obtain a lubricant, wherein the organic polymer is a synthetic polymer in the form of a polycarboxylate which is a polyacrylic acid.
 
7. Use of a lubricant according to any one of claims 1 to 5 for the fitting of concrete pipes.
 


Ansprüche

1. Wasserbasiertes Schmiermittel, umfassend 20 bis 75 Gew.-% Wasser, 5 bis 20 Gew.-% mindestens eines organischen Polymers, 10 bis 35 Gew.-% mindestens eines mehrwertigen Alkohols und weniger als 1 Gew.-% eines Öls, wobei das organische Polymer ein synthetisches Polymer in Form eines Polycarboxylats ist, bei welchem es sich um eine Polyacrylsäure handelt.
 
2. Wasserbasiertes Schmiermittel nach Anspruch 1, wobei das Schmiermittel weniger als 0,5 Gew.-% und weiter bevorzugt weniger als 0,1 Gew.-% eines Öls umfasst.
 
3. Wasserbasiertes Schmiermittel nach einem der vorhergehenden Ansprüche, wobei es sich bei dem mehrwertigen Alkohol um Propylenglykol handelt.
 
4. Wasserbasiertes Schmiermittel nach einem der vorhergehenden Ansprüche, ferner umfassend einen Stabilisator, vorzugsweise eine alkoxylierte Cellulose.
 
5. Wasserbasiertes Schmiermittel nach einem der vorhergehenden Ansprüche, ferner umfassend mindestens ein Additiv, das aus kolloidalem Siliciumdioxid ausgewählt ist.
 
6. Verfahren zur Herstellung eines wasserbasierten Schmiermittels nach einem der Ansprüche 1 bis 5, bei dem man Wasser mit mindestens einem organischen Polymer und mindestens einem mehrwertigen Alkohol unter Erhalt eines Schmiermittels mischt, wobei das organische Polymer ein synthetisches Polymer in Form eines Polycarboxylats ist, bei welchem es sich um eine Polyacrylsäure handelt.
 
7. Verwendung eines Schmiermittels nach einem der Ansprüche 1 bis 5 zum Zusammenfügen von Betonrohren.
 


Revendications

1. Lubrifiant à base d'eau comprenant de 20 à 75 % en poids d'eau, 5 à 20 % en poids d'au moins un polymère organique, 10 à 35 % en poids d'au moins un alcool polyhydrique et moins de 1 % en poids d'une huile, le polymère organique étant un polymère synthétique sous forme d'un polycarboxylate qui est un poly(acide acrylique).
 
2. Lubrifiant à base d'eau selon la revendication 1, le lubrifiant comprenant moins de 0,5 % en poids, plus préférablement moins de 0,1 % en poids d'une huile.
 
3. Lubrifiant à base d'eau selon l'une quelconque des revendications précédentes, l'alcool polyhydrique étant le propylèneglycol.
 
4. Lubrifiant à base d'eau selon l'une quelconque des revendications précédentes comprenant en outre un stabilisant, préférablement une cellulose alcoxylée.
 
5. Lubrifiant à base d'eau selon l'une quelconque des revendications précédentes, comprenant en outre au moins un additif choisi parmi de la silice colloïdale.
 
6. Procédé pour la préparation d'un lubrifiant à base d'eau selon l'une quelconque des revendications 1 à 5, comprenant le mélange d'eau avec au moins un polymère organique et au moins un alcool polyhydrique pour obtenir un lubrifiant, le polymère organique étant un polymère synthétique sous forme d'un polycarboxylate qui est un poly(acide acrylique).
 
7. Utilisation d'un lubrifiant selon l'une quelconque des revendications 1 à 5 pour le raccord de tuyaux en béton.
 






Cited references

REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description