EP1513916B1 - Use of copolymers containing alkylene oxide units, as an additive in dishwashing compositions - Google Patents

Abstract

The use of copolymers containing alkylene oxide units and (mole%): (a) acrylic acid and/or one of its a water soluble (50-93), (b) methacrylic acid and/or one of its a water soluble salts (5-30), and (c) at least one nonionic monomer (2-20), statistically or block polymerized as washing and cleaning material additives is new. The use of copolymers containing alkylene oxide units and (mole%): (a) acrylic acid and/or one of its water soluble salts (50-93); (b) methacrylic acid and/or one of its a water soluble salts (5-30); and (c) at least one nonionic monomer (2-20) of formula (I). R1 = H or Me, R2 = chemical bond or optionally branched 1-6C alkylene, R3 = optionally branched 2-4C alkylene, R4 = optionally branched 1-6C alkyl, n = 3-50, statistically or block polymerized as washing and cleaning material additives. An Independent claim is also included for a washing and cleaning material containing the copolymer as a coating inhibiting additive.

Description

• (a) 50 bis 93 mol-% Acrylsäure und/oder eines wasserlöslichen Salzes der Acrylsäure,
• (b) 5 bis 30 mol-% Methacrylsäure und/oder eines wasserlöslichen Salzes der Methacrylsäure
  und
• (c) 2 bis 20 mol-% mindestens eines nichtionischen Monomers der Formel I
  
  in der die Variablen folgende Bedeutung haben:

  R¹

  Wasserstoff oder Methyl;

  R²

  eine chemische Bindung oder unverzweigtes oder verzweigtes C₁-C₆-Alkylen;

  R³

  gleiche oder verschiedene unverzweigte oder verzweigte C₂-C₄-Alkylenreste;

  R⁴

  unverzweigtes oder verzweigtes C₁-C₆-Alkyl;

  n

  3 bis 50,

statistisch oder blockweise einpolymerisiert enthalten, als Zusatz zu maschinellen Geschirrspülmitteln.The present invention relates to the use of copolymers containing alkylene oxide units, which

• (a) from 50 to 93 mol% of acrylic acid and / or of a water-soluble salt of acrylic acid,
• (B) 5 to 30 mol% of methacrylic acid and / or a water-soluble salt of methacrylic acid
  and
• (c) 2 to 20 mol% of at least one nonionic monomer of the formula I.
  
  in which the variables have the following meaning:

  R ¹

  Hydrogen or methyl;

  R ²

  a chemical bond or straight or branched C ₁ -C ₆ alkylene;

  R ³

  identical or different unbranched or branched C ₂ -C ₄ -alkylene radicals;

  R ⁴

  unbranched or branched C ₁ -C ₆ -alkyl;

  n

  3 to 50,

in copolymerized form, randomly or in blocks, as an additive to automatic dishwashing detergents.

In addition, the invention relates to automatic dishwashing compositions which contain these copolymers as a deposit-inhibiting additive.

In the automatic dishwashing, the items to be washed in residue-free cleaned state with flawless glossy surface incurred, for which usually a cleaner, a rinse aid and Regeneriersalz must be used for water softening.

The so-called "2inl" dishwashing detergents introduced on the market contain, in addition to the cleaner for removing stains on the items to be washed, integrated rinse aid surfactants which during the rinse and drying cycle ensure a flat flow of water on the items to be washed and thus prevent limescale and water stains. Refilling a rinse aid is no longer necessary when using these products.

Modern machine dishwashing detergents, "3inl" cleaners, are intended to combine the three functions of cleaning, rinsing and water softening in a single detergent formulation, making it unnecessary for the consumer to replenish salt with water hardnesses of 1 to 3. To bind the hardness-forming calcium and magnesium ions, sodium tripolyphosphate is usually added to these cleaners. This in turn, however, results in calcium and magnesium phosphate deposits on the items to be washed.

EP-A-324 568 describes water-soluble copolymers for detergents and cleaners which are obtained by polymerization of acrylic acid, methacrylic acid and alkoxypolyethylene glycol methacrylates which have a long-chain alkoxy radical and / or a long-chain polyethylene glycol block in the presence of isopropanol. The alkoxypolyethylene glycol methacrylate content of these copolymers is <1 mol%.

According to JP-A-1991/185184, copolymers based on at least one monomer from the group of maleic acid, acrylic acid and methacrylic acid and an optionally methoxy- or ethoxylated polyethylene glycol (meth) acrylate as further monomer having an average molecular weight M _w of 1,000 up to 10 000, are used for the desizing, cleaning, bleaching and dyeing of natural and synthetic bevels. Specifically disclosed are copolymers of acrylic acid and methoxypolyethylene glycol methacrylate.

JP-A-2000/24691 describes copolymers of unsaturated carboxylic acids and monomers containing polyalkylene oxide units with average molecular weights M _w of> 50,000 to 3,000,000 as agents against, in particular, silicates-based scale in water circulations, eg cooling systems. In detail In turn, only copolymers of acrylic acid and methoxypolyethylene glycol methacrylate are disclosed.

The invention was based on the object to remedy the above problems and to provide an additive that can be used advantageously especially in multi-function cleaners and in particular shows a deposit-inhibiting effect.

• (a) 50 bis 93 mol-% Acrylsäure und/oder eines wasserlöslichen Salzes der Acrylsäure,
• (b) 5 bis 30 mol-% Methacrylsäure und/oder eines wasserlöslichen Salzes der Methacrylsäure
  und
• (c) 2 bis 20 mol-% mindestens eines nichtionischen Monomers der Formel I
  
  in der die Variablen folgende Bedeutung haben:

  R¹

  Wasserstoff oder Methyl;

  R²

  eine chemische Bindung oder unverzweigtes oder verzweigtes C₁-C₆-Alkylen;

  R³

  gleiche oder verschiedene unverzweigte oder verzweigte C₂-C₄-Alkylenreste;

  R⁴

  unverzweigtes oder verzweigtes C₁-C₆-Alkyl;

  n

  3 bis 50,

statistisch oder blockweise einpolymerisiert enthalten, als Zusatz zu maschinellen Geschirrspülmitteln gefunden.Accordingly, the use of copolymers containing alkylene oxide units, the

• (a) from 50 to 93 mol% of acrylic acid and / or of a water-soluble salt of acrylic acid,
• (B) 5 to 30 mol% of methacrylic acid and / or a water-soluble salt of methacrylic acid
  and
• (c) 2 to 20 mol% of at least one nonionic monomer of the formula I.
  
  in which the variables have the following meaning:

  R ¹

  Hydrogen or methyl;

  R ²

  a chemical bond or straight or branched C ₁ -C ₆ alkylene;

  R ³

  identical or different unbranched or branched C ₂ -C ₄ -alkylene radicals;

  R ⁴

  unbranched or branched C ₁ -C ₆ -alkyl;

  n

  3 to 50,

contained in copolymerized form, randomly or in blocks, as an additive to automatic dishwashing detergents.

Furthermore, automatic dishwashing agents were found which contain the copolymers containing alkylene oxide units as a deposit-inhibiting additive.

The copolymers containing alkylene oxide units contain as copolymerized components (a) and (b) acrylic acid or methacrylic acid and / or water-soluble salts of these acids, in particular the alkali metal salts, such as potassium and especially sodium salts, and ammonium salts.

The proportion of acrylic acid (a) in the copolymers to be used according to the invention is 50 to 93 mol%, preferably 65 to 85 mol% and particularly preferably 65 to 75 mol%.

Methacrylic acid (b) is contained in the copolymers to be used according to the invention to 5 to 30 mol%, preferably to 10 to 25 mol% and especially to 15 to 25 mol%.

in der die Variablen folgende Bedeutung haben:

R¹

Wasserstoff oder bevorzugt Methyl;

R²

unverzweigtes oder verzweigtes C₁-C₆-Alkylen oder bevorzugt eine chemische Bindung;

R³

gleiche oder verschiedene unverzweigte oder verzweigte C₂-C₄-Alkylenreste, vor allem C₂-C₃-Alkylenreste, insbesondere Ethylen;

R⁴

unverzweigtes oder verzweigtes C₁-C₆-Alkyl, bevorzugt C₁-C₂-Alkyl;

n

3 bis 50, bevorzugt 5 bis 40, besonders bevorzugt 10 bis 30.

The copolymers contain as component (c) nonionic monomers of the formula I.

in which the variables have the following meaning:

R ¹

Hydrogen or preferably methyl;

R ²

unbranched or branched C ₁ -C ₆ -alkylene or preferably a chemical bond;

R ³

identical or different unbranched or branched C ₂ -C ₄ -alkylene radicals, especially C ₂ -C ₃ -alkylene radicals, in particular ethylene;

R ⁴

unbranched or branched C ₁ -C ₆ -alkyl, preferably C ₁ -C ₂ -alkyl;

n

3 to 50, preferably 5 to 40, particularly preferably 10 to 30.

Particularly suitable examples of the monomers II are: methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, methoxypolybutylene glycol (meth) acrylate, methoxypoly (propylene oxide-co-ethylene oxide) (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, ethoxypolypropylene glycol ( meth) acrylate, ethoxypolybutylene glycol (meth) acrylate and Ethoxypoly (propylene oxide-co-ethylene oxide) (meth) acrylate, with methoxypolyethylene glycol (meth) acrylate and Methoxypolypropylenglykol (meth) acrylate are preferred and Methoxypolyethylenglykolmethacrylat is particularly preferred.

The polyalkylene glycols contain 3 to 50, in particular 5 to 40 and especially 10 to 30 alkylene oxide units.

The proportion of nonionic monomers (c) in the copolymers to be used according to the invention is 2 to 20 mol%, preferably 5 to 15 mol% and especially 5 to 10 mol%.

The copolymers to be used according to the invention generally have an average molecular weight M _{w of} from 3,000 to 50,000, preferably from 10,000 to 30,000 and more preferably from 15,000 to 25,000.

The K value of the copolymers is usually from 15 to 40, in particular from 20 to 35, especially from 27 to 30 (measured in 1 wt .-% aqueous solution at 25 ° C, according to H. Fikentscher, cellulose chemistry, Vol. 13, pp. 58-64 and 71-74 (1932)).

The copolymers to be used according to the invention can be prepared by free-radical polymerization of the monomers.
It can be worked by all known radical polymerization. In addition to the bulk polymerization, the methods of solution polymerization and emulsion polymerization should be mentioned in particular, with the solution polymerization being preferred.

The polymerization is preferably carried out in water as a solvent. However, it can also be carried out in alcoholic solvents, in particular C ₁ -C ₄ -alcohols, such as methanol, ethanol and isopropanol, or mixtures of these solvents with water.

Suitable polymerization initiators are both thermally and photochemically (photoinitiators) decomposing and thereby radical-forming compounds.

Among the thermally activatable polymerization initiators, preference is given to initiators having a decomposition temperature in the range from 20 to 180.degree. C., in particular from 50 to 90.degree. Examples of suitable thermal initiators are inorganic peroxo compounds, such as peroxodisulfates (ammonium and preferably sodium peroxodisulfate), peroxosulfates, percarbonates and hydrogen peroxide; organic peroxy compounds, such as diacetyl peroxide, di-tert-butyl peroxide, Diamyl peroxide, dioctanoyl peroxide, didecanoyl peroxide, dilauroyl peroxide, dibenzoyl peroxide, bis (o-toloyl) peroxide, succinyl peroxide, tert-butyl peracetate, tert-butyl permalate, tert-butyl perisobutyrate, tert-butyl perpivalate, tert-butyl peroctoate, tert-butyl perneodecanoate, tert-butyl perbenzoate, tert-butyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-butyl peroxy-2-ethylhexanoate and diisopropyl peroxydicarbamate; Azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile) and azobis (2-amidopropane) dihydrochloride.

These initiators can be used in combination with reducing compounds as starter / regulator systems. Examples of such reducing compounds include phosphorus-containing compounds such as phosphorous acid, hypophosphites and phosphinates, sulfur-containing compounds such as sodium hydrogen sulfite, sodium sulfite and sodium formaldehyde sulfoxilate, and hydrazine.

Examples of suitable photoinitiators are benzophenone, acetophenone, benzoin ethers, Benzyldialkylketone and derivatives thereof.

Preferably, thermal initiators are used, with inorganic peroxo compounds, in particular sodium peroxodisulfate (sodium persulfate), being preferred. The peroxo compounds are particularly advantageously used in combination with sulfur-containing reducing agents, in particular sodium hydrogen sulfite, as the redox initiator system. When using this starter / regulator system copolymers are obtained which contain as end groups -SO ₃ ^- Na ⁺ and / or -SO ₄ ^- Na ⁺ and are characterized by particular cleaning power and deposit-inhibiting effect.

Alternatively, phosphorus-containing starter / regulator systems may also be used, e.g. Hypophosphites / phosphinates.

The amounts of photoinitiator or starter / regulator system are to be matched to the substances used in each case. If, for example, the preferred system peroxodisulfate / hydrogen sulfite is used, usually 2 to 6% by weight, preferably 3 to 5% by weight, of peroxodisulfate and generally 5 to 30% by weight, preferably 5 to 10% by weight. %, Hydrogen sulfite, in each case based on the monomers (a), (b) and (c) used.

If desired, polymerization regulators can also be used. Suitable compounds are those known in the art, for example sulfur compounds, such as mercaptoethanol, 2-ethylhexyl thioglycolate, thioglycolic acid and dodecyl mercaptan. When polymerization regulator their amount used is usually 0.1 to 15 wt .-%, preferably 0.1 to 5 wt .-% and particularly preferably 0.1 to 2.5 wt .-%, based on the monomers (a ), (b) and (c).

The polymerization temperature is usually at 30 to 200 ° C, preferably at 50 to 150 ° C and particularly preferably at 80 to 120 ° C.

The polymerization may be carried out under atmospheric pressure, but is preferably carried out in the closed system under the evolving autogenous pressure.

In the preparation of the copolymers to be used according to the invention, the monomers (a), (b) and (c) can be used as such, but it is also possible to use reaction mixtures which are obtained in the preparation of the monomers (c). For example, instead of methoxypolyethylene glycol methacrylate, the monomer mixture obtained in the esterification of polyethylene glycol monomethyl ether with an excess of methacrylic acid can be used. Advantageously, the esterification can also be carried out in situ in the polymerization mixture by (1) combining acrylic acid, (2) a mixture of methacrylic acid and polyethylene glycol monomethyl ether and (3) free radical initiator in parallel. If appropriate, a catalyst necessary for the esterification, such as methanesulfonic acid or p-toluenesulfonic acid, may additionally be used.

The copolymers to be used according to the invention may also be obtained by polymer-analogous reaction, e.g. by reacting an acrylic acid / methacrylic acid copolymer with polyalkylene glycol monoalkyl ether. However, preferred is the radical copolymerization of the monomers.

If desired for the application, the aqueous solutions obtained in the preparation of the carboxylic acid group-containing copolymers to be used according to the invention can be neutralized or partially neutralized by addition of base, in particular of sodium hydroxide solution, i. adjusted to a pH in the range of 4-8, preferably 4.5-7.5.

The copolymers used according to the invention are outstandingly suitable as an additive to automatic dishwasher detergents. They are characterized mainly by their deposit-inhibiting effect against both inorganic and organic coatings. In particular, coverings caused by the remaining constituents of the detergent formulation are such as toppings of calcium and magnesium phosphate, calcium and magnesium silicate and calcium and magnesium phosphonate, and linings derived from the soil constituents of the rinse liquor, such as fat, protein and starch deposits, called. The copolymers used according to the invention thereby also increase the detergency of the dishwashing detergent. In addition, they already facilitate the drainage of the water from the dishes at low concentrations, so that the proportion of rinse aid surfactants in the dishwashing detergent can be reduced. When using the copolymers containing sulfonic acid accordingly particularly clear glasses and high-gloss metal cutlery are obtained, especially when the dishwasher is operated without Regeneriersalz for water softening. The copolymers containing sulfonic acid groups can therefore be used advantageously not only in 2-in-1 cleaners but also in 3-in-1 cleaners.

The copolymers used according to the invention can be used directly in the form of the aqueous solutions obtained in the preparation as well as in dried, e.g. by spray drying, fluidized spray drying, drum drying or freeze-drying obtained form are used. The automatic dishwashing agents of the invention may accordingly be in solid or liquid form, e.g. as powders, granules, extrudates, tablets, liquids or gels.

Examples A) Preparation of copolymers containing alkylene oxide units example 1

In a reactor with nitrogen feed, reflux condenser and metering device, a mixture of 619 g of distilled water and 2.2 g of phosphorous acid was heated to 100 ° C internal temperature with nitrogen and stirring. Then, in parallel were (1) a mixture of 123.3 g of acrylic acid and 368.5 g of distilled water, (2) a mixture of 18.4 g of sodium peroxodisulfate and 164.6 g of distilled water, (3) a mixture of 72.0 g of water, 49.1 g of methacrylic acid and 166.9 g of methoxypolyethylene glycol methacrylate (M _w = 1 100) and (4) 46 g of a 40 wt .-% aqueous sodium hydrogen sulfite continuously added in 5 h. After two hours of stirring at 100 ° C, the reaction mixture was cooled to room temperature and adjusted by the addition of 190 g of 50 wt .-% sodium hydroxide solution to a pH of 7.2.

There was obtained a slightly yellowish, clear solution of a copolymer having a solids content of 25.7 wt .-% and a K value of 27.2 (1 wt .-% aqueous solution, 25 ° C).

Example 2

In the reactor of Example 1, a mixture of 221.6 g of distilled water and 1.1 g of phosphorous acid was heated with nitrogen and stirring to 100 ° C internal temperature. Then, in parallel, (1) a mixture of 38.6 g of acrylic acid and 231.0 g of distilled water, (2) a mixture of 29.6 g of toluene, 27.7 g of methacrylic acid and 116.6 g of methoxypolyethylene glycol methacrylate (M _w = 1 100) and (3) 68.6 g of a 40 wt .-% aqueous sodium bisulfite solution continuously added in 5 h. In parallel, a mixture of 9.1 g of sodium peroxodisulfate and 82.3 g of distilled water was added in 5.25 hours. In parallel to these feeds, a mixture of water and toluene was distilled off continuously, the water was returned to the reaction (removal of the toluene).

After stirring for one hour at 100 ° C, the reaction mixture was cooled to room temperature and adjusted by addition of 85 g of 50 wt .-% sodium hydroxide solution to a pH of 7.2.

There was obtained a clear polymer solution having a solids content of 28.8 wt .-% and a K value of 28.9 (1 wt .-% aqueous solution, 25 ° C).

B) Use of copolymers containing alkylene oxide units in dishwashing detergents

To test their scale-inhibiting effect, the resulting copolymers were used together with a dishwashing detergent formulation of the following composition: 50% by weight Sodium tripolyphosphate (Na ₃ P ₃ O ₁₀ .6H ₂ O) 27% by weight sodium 3% by weight Sodium disilicate (x Na ₂ O.y SiO ₂ ; x / y = 2.65; 80%) 6% by weight Sodium percarbonate (Na ₂ CO ₃ · 1.5H ₂ O ₂ ) 2% by weight Tetraacetylenediamine (TAED) 2% by weight Low-foaming nonionic surfactant based on fatty alcohol alkoxylates 3% by weight sodium chloride 5% by weight sodium sulphate 2% by weight Polyacrylic acid sodium salt (M _w 8 000)

The test was carried out at the following rinsing conditions without the addition of ballast dirt, with neither rinse aid nor regeneration salt were used: flushing: Dishwasher: Miele G 686 SC rinses: 2 rinses 55 ° C normal (without pre-rinse) ware: Knife (WMF table knife Berlin, Monoblock) and barrel-shaped glass beaker (Matador, Ruhr Kristall) Dishwashing liquid: 21 g copolymer: 4.2 g Rinse temperature: 65 C. Water hardness: 25 ° dH

The washware was evaluated 18 hours after cleaning by visual inspection in a black painted light box with halogen spot and pinhole using a grading scale from 10 (very good) to 1 (very bad). The highest grade of 10 corresponds to covering and drip-free surfaces, from grades <5, coverings and drops are already visible under normal room lighting, so are perceived as disturbing.

The test results obtained are summarized in the following table. table Copolymer from Ex. Rating (grade) knife glasses 1 8.0 7.7 2 6.2 7.5 - 4.0 4.0

Claims (8)

1. The use of copolymers comprising alkylene oxide units which comprise

   (a) 50 to 93 mol% of acrylic acid and/or a water-soluble salt of acrylic acid,

   (b) 5 to 30 mol% of methacrylic acid and/or a water-soluble salt of methacrylic acid
   and

   (c) 2 to 20 mol% of at least one nonionic monomer of formula I

   

   in which the variables have the following meanings:

   R¹ is hydrogen or methyl;

   R² is a chemical bond or unbranched or branched C₁-C₆-alkylene;

   R³ are identical or different unbranched or branched C₂-C₄-alkylene radicals;

   R⁴ is unbranched or branched C₁-C₆-alkyl;

   n is 3 to 50,

   in random or block copolymerized form, as additive for machine dishwashing detergents.
2. The use according to claim 1, wherein the copolymers comprise 65 to 85 mol% of component (a), 10 to 25 mol% of component (b) and 5 to 15 mol% of component (c) in copolymerized form.
3. The use according to claim 1 or 2, wherein the copolymers comprise 65 to 75 mol% of component (a), 15 to 25 mol% of component (b) and 5 to 10 mol% of component (c) in copolymerized form.
4. The use according to claims 1 to 3, wherein the copolymers comprise, as component (c), a nonionic monomer of the formula I in which R¹ is methyl, R² is a chemical bond, R³ is C₂-C₃-alkylene, R⁴ is C₁-C₂-alkyl and n is 5 to 40, in copolymerized form.
5. The use according to claims 1 to 4, wherein the copolymers comprise, as component (c), a nonionic monomer of the formula I in which R¹ is methyl, R² is a chemical bond, R³ is ethylene, R⁴ is methyl and n is 10 to 30, in copolymerized form.
6. The use according to claims 1 to 5, wherein the copolymers comprise -SO₃ ^- Na⁺ and/or -SO₄ ^- Na⁺ as end-groups.
7. The use according to claims 1 to 6, wherein the copolymers are used as deposit-inhibiting additive in machine dishwashing detergents.
8. A machine dishwashing detergent which comprises copolymers according to claims 1 to 7 as deposit-inhibiting additive.