Patent Application
20060094805
The invention relates to esters and partial esters of polyhydric alcohols and carboxylic acids and their use.
Esters of polyols and of long-chain carboxylic acids, in particular fatty acids, have been known for a long time and are widely used in industry. Examples of these are natural and synthetic glycerol esters of fatty acids, pentaerythritol tetrastearate, diglycerol stearates, oleates, pentaerythritol montanate, trimethylolpropane montanate, and many other compounds.
Many of these products are used in plastics processing, and sometimes products based on fatty acids are used alongside products based on montan wax acid, because their performance characteristics are complementary.
The fatty acids are single-chain-length products or products used with a chain length distribution, the chain lengths being C8-C18, and in exceptional cases saturated C22 and unsaturated C22 are also available.
The very important product montan wax acid is a mixture of long-chain carboxylic acid having from 24 to 34 carbon atoms, produced during the refining of montan wax.
The chain length distribution of the acids (i.e. fatty acids and montan wax acid) cause the derivatives of these acids to behave differently in plastics. The highly polar fatty acid derivatives have better compatibility in polar plastics and tend to act internally, while montan wax acid derivatives with their longer alkyl chains are less polar than fatty acid derivatives and tend to act externally in polar plastics. Both modes of action are desired and required for processing.
Lower molecular weight makes fatty derivatives more polar than montan derivatives. “Internal” and “external action” are terms especially used in the processing of PVC or of other plastics, relating to the site of action of lubricants. Internal agents act within the melt or in the case of PVC within the polymer grains, while external lubricants act at the melt/mold phase boundary and then also act as release agents. Non-polar lubricants act externally in polar plastics, while polar lubricants act externally in non-polar plastics, and vice versa.
Montan wax derivatives generally exhibit marked intrinsic color, and this generally prevents their use in transparent applications. Fatty acid esters have only slight intrinsic color, but, because their chain length is relatively short, are often too polar and too mobile or too volatile when subjected to high temperature.
There has therefore long been a desire for products with montan wax properties and little intrinsic color, or for products which have as little intrinsic color as fatty derivatives and have the properties of montan wax derivatives.
Surprisingly, it has now been found that esters whose molecule simultaneously contains both types of carboxylic acid (fatty acid and montan wax acid) exhibit the abovementioned desired properties.
The invention therefore provides esters and partial esters of the type mentioned at the outset, which contain at least one carboxylic acid radical and/or a radical of a carboxylic acid mixture having from 24 to 34 carbon atoms (component B) and contain at least one carboxylic acid radical and/or a radical of a carboxylic acid mixture having from 8 to 22 carbon atoms (component C).
The polyhydric alcohol preferably has from 3 to 12 hydroxy groups.
The polyhydric alcohol is preferably trimethylolpropane, trimethylolethane, pentaerythritol, glycerol, diglycerol, polyglycerol, sorbitol, dipentaerythritol, ditrimethylolpropane, and/or ethoxylated derivatives of these.
The polyhydric alcohol is particularly preferably trimethylolpropane, glycerol, and/or pentaerythritol.
The radical of the carboxylic acid mixture (component C) preferably contains from 8 to 18 carbon atoms.
The esters and partial esters also preferably contain at least one dicarboxylic acid radical and/or the radical of a dicarboxylic acid mixture (component D).
The dicarboxylic acid radical and/or the radical of the dicarboxylic acid mixtures preferably derive from compounds such as adipic acid, dodecanedioic acid, or dimer fatty acid.
The esters and partial esters of the present invention preferably have an acid number of from 5 to 25.
The esters and partial esters of the present invention preferably have a hydroxy number of from 5 to 400 (defined by DGF method M-IV-6 (57)).
The esters and partial esters of the present invention particularly preferably have a hydroxy number of from 5 to 150.
The invention also provides the use of ester or partial ester of the present invention as processing aid or in the processing of plastics.
The plastics are preferably thermoplastics.
The thermoplastics are particularly preferably polyvinyl chloride, polyester, polycarbonate, polyamide, or polypropylene.
The inventive esters and partial esters may be used as dispersing agents for pigments, and also as lubricants in the processing of plastics.
They may also be used for preparation of micronizates.
As is well known, the reaction of polyhydric alcohols with carboxylic acids to give esters always produces mixtures of esters having different degrees of esterification. If the reaction uses alcohols having three or more alcohol functions, e.g. trimethylolpropane, pentaerythritol, glycerol, sorbitol, ditrimethylolpropane, dipentaerythritol, diglycerol, or polyglycerol, it is possible, using a two-stage process and an acidic catalyst, first to prepare the partial esters of the high-molecular-weight acid (component B) and then to react all of the remaining, or some of the free, hydroxy groups with the more reactive low-molecular-weight acid (component C). This gives a polyol ester or, respectively, a partial ester in which carboxylic acids having from 8 to 22 and from 24 to 34 carbon atoms are incorporated in a specific manner.
Mixed esters of a polyol and of different carboxylic acid molecules, such as fatty acid or montan wax acid, which still contain free hydroxy functions can then be reacted with dibasic carboxylic acids (component D), such as adipic acid, dodecanedioic acid, or dimer fatty acid, to give oligomers.
The principle does not work with dihydric alcohols, because in that case the product is inevitably always diesters which contain only one type of carboxylic acid.
If an Sn-containing catalyst is used for the esterification process, the reaction can then also be carried out in a single-step process.
Examples of preparation of the inventive esters and partial esters.
Process:
Montan wax acid (1.5 mol) was melted at 100° C. and trimethylolpropane (1 mol) and 70% strength methanesulfonic acid (0.2% by weight) were added at that temperature and the mixture was then heated to 120° C. The mixture was inertized with N2, and stirred for 3 hours while the water of reaction was removed by distillation, and then tallow fatty acid (1.2 mol) was added and the mixture was esterified until the acid number had fallen below 12. The catalyst was neutralized with 30% strength NaOH, and the final product was dried and filtered.
Montan wax acid (1.1 mol) and tallow fatty acid (1.2 mol) were melted at 100° C., and glycerol (1 mol) and Fascat 2001 (0.1% by weight) were added at that temperature, and the mixture was then heated to 190° C. The mixture was inertized with N2, and stirred while the water of reaction was removed by distillation, until the acid number had fallen below 15, then cooled to 120° C. and filtered.
Montan wax acid (1.5 mol) and tallow fatty acid (2 mol) were melted at 100° C., and pentaerythritol (1 mol) and Fascat 2001 (0.1% by weight) were added at that temperature, and the mixture was then heated to 190° C. The mixture was inertized with N2, and stirred while the water of reaction was removed by distillation, until the acid number had fallen below 20, then cooled to 120° C. and filtered.
Montan wax acid (1.1 mol) and tallow fatty acid (2 mol) were melted at 100° C., and pentaerythritol (1 mol) and Fascat 2001 (0.1% by weight) were added at that temperature, and the mixture was then heated to 190° C. The mixture was inertized with N2, and stirred while the water-of reaction was removed by distillation, until the acid number had fallen below 40, the mixture then being treated with adipic acid and esterified until the AN had fallen below 20, then cooled to 120° C. and filtered.
AN = Acid number to DIN 53402
SN = Saponification number to DIN 53401
FH = Flow hardness
Dp = Drop point ° C. to DIN 51801/2
MV = Melt viscosity at 100° C. to DIN 51562
The products prepared by the processes described were tested in the processing of various plastics, and when compared with pure montan wax derivatives exhibited an improvement in color properties without any significant losses in performance.
Applications Testing
* ®Loxiol G70S from Cognis
** ®Licolub WE 40 from Clariant GmbH
* ®Loxiol G70S from Cognis
** ®Licolub WE 40 from Clariant GmbH
The following mixing specification (in % by weight) was used for the measurements and test results in Table 3 to 5:
Test product ({circumflex over (=)} ester type) optionally 0.3 or 05.% by weight
* ®Loxiol G70S from Cognis
** ®Licolub WE 40 from Clariant GmbH
* ®Loxiol G70S from Cognis
** ®Licolub WE 40 from Clariant GmbH
| Number | Date | Country | Kind |
|---|---|---|---|
| 102 45 623.2 | Sep 2002 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP03/10502 | 9/22/2003 | WO | 3/30/2005 |
