THICKENED POLYMER

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of application Ser. No. 13/700,406, which is a National Stage of International Application PCT/EP2011/054247, filed Mar. 21, 2011; the entire disclosures of both applications are expressly incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a new type of thickening polymer with special properties which is free from associative monomers and/or whose chain contains no such associative monomers.

Definitions

Unless stated otherwise, all quantitative data are percentages by mass based on the total mass of the preparation.

Within the context of the present specification, associative monomers are monomers of the type U-S-L, where U contains an ethylenically unsaturated group such as methacrylate, acrylate, allyl or vinyl groups, S is a spacer from a polyoxyalkylene chain having 2 to 300 alkyleneoxy units such as polyethylene glycol, polypropylene glycol or polybutylene glycol, and L is a hydrophobic group such as an alkyl and/or aryl group, which has at least 4, preferably at least 8 carbon atoms, for example a lauryl group.

Within the context of the present specification, tan δ value means the quotient of the loss modulus and the storage modulus, in each case measured at 40° C. The measuring device used here is not important. The values given in this specification were determined using the Malvern Gemini HR nano.

2. Discussion of Background Information

In general, thickening polymers serve to thicken water or water-containing preparations. In this connection, the water allows the polymers to swell to gels in order, in so doing, to influence viscosity and flow behavior. Thickening polymers are of importance in the manufacture of body cleansing compositions, creams, cleaning compositions, finishes, printing inks, coatings, emulsion paints and other coating materials, adhesives, paper, foods and so on.

Known from EP 1465932 B1 were alkali-swellable and alkali-soluble associative multipurpose polymers which is the polymerization product of a monomer mixture of

• a) at least one acid-containing vinyl monomer,
• b) at least one nonionic vinyl monomer,
• c) a first associative monomer which has a first hydrophobic end group,
• d) a second associative monomer with a second hydrophobic end group, a semi-hydrophobic monomer and of a combination thereof and optionally
• e) one or more crosslinking monomers or chain-transfer agents.

Such polymers are prepared by emulsion polymerization. For this, firstly the monomer mixture is emulsified or suspended with a surfactant in water in the form of micelles. The actual reactor is charged with the initiator in aqueous solution or suspension, and the monomer suspension is slowly added. The rate at which the monomer is added is controlled so as to avoid a considerable increase in the reaction temperature as a result of the Trommsdorff effect (gel effect). The gel effect arises in the event of too great an increase in the conversion and leads to the rate of the polymerization increasing as a result of diffusion of the polymer radicals being hindered, and the polymerization in itself is accelerated. Attempts are made to prevent this for reasons of safety and to obtain a narrow molar mass distribution. If the gel effect does arise, then a bimodal molar mass distribution is obtained. Further prior art can be found in EP 1272159, WO03062288, WO03061615, WO03062288, WO2007090759, U.S. Pat. No. 6,242,531.

Thickening polymers with which it is possible to thicken aqueous preparations such that gels which are as clear as possible are formed are desirable.

Thickening polymers with which tan δ values which are as low as possible can be achieved in aqueous solution are also desirable.

Thickening polymers with a considerably extended storage stability are likewise desirable.

The prior art lacked thickening polymers which make it possible to produce clear gels coupled with simultaneously low tan δ values.

SUMMARY OF THE INVENTION

Surprisingly and unforeseeably to the person skilled in the art, it has now been found that a polymer obtainable by free-radical emulsion polymerization of

(A) at least one acidic vinyl monomer or salt thereof,

(B) at least one nonionic vinyl monomer, particularly preferably a hydrophobic nonionic vinyl monomer,

(C) at least one monomer containing an unsaturated end group and a polyoxyalkylene portion,

(D) at least one crosslinking monomer,

(E) optionally a protective colloid, characterized in that the polymerization is controlled such that at least at times the gel effect arises, achieved by the fact that the monomer addition (dosing time) takes place over the course of 40 minutes, particularly preferably over the course of 30 minutes, overcomes the defects of the prior art. In the case of such a polymerization utilizing the Trommsdorff effect, i.e. with the constant addition of the monomers and simultaneously high addition rate of the monomers, a monomer excess is formed which leads to an autoacceleration of the polymerization (Trommsdorff effect). The result is an increase in the molecular weights coupled with simultaneously advantageous morphology of the polymers. In this connection, it is particularly preferred if (F) associative monomers are not present or have at most a concentration of 15% by weight, preferably 10% by weight, particularly preferably 5% by weight, very particularly preferably 2.5% by weight, very extraordinarily preferably 1% by weight, very particularly extraordinarily preferably 0.1% by weight. It is particularly preferred if the acidic vinyl monomer (A) is selected from vinyl monomers with carboxyl groups, particularly preferably acrylic acid or methacrylic acid or alkali metal, alkaline earth metal, ammonium or alkylammonium salts thereof, very particularly preferably methacrylic acid or alkali metal, alkaline earth metal, ammonium or alkylammonium salts thereof. It is particularly preferred if the nonionic vinyl monomer (B) is selected from C1-C22-alkyl (meth)acrylates and mixtures thereof. As a result, good flow properties and thus an advantageous rheological profile are achieved.

Additional long-chain alkyl acrylates (C12 and C18) are particularly preferred because they increase the viscosity that can be achieved. It is particularly preferred if the monomer (C) containing an unsaturated end group and a polyoxyalkylene portion is selected from vinylpolyalkylene glycols or polymerizable surfactants or mixtures thereof, is particularly preferably selected from R307, RAL307, A11/1800, R1100, A111R, AB25-8. It is particularly preferred if the crosslinking monomer (D) is selected from polyol (meth)acrylates with at least two (meth)acrylate groups and the mixed esters of polyols with acrylic acid and/or methacrylic acid. It is further particularly preferred if the monomers (A) are present in contents of from 10 to 75%, preferably 30 to 50%, particularly preferably 35 to 49%, (B) are present in contents of from 10 to 90%, preferably 30 to 80%, particularly preferably 47 to 60%, (C) are present in contents of from 0.5 to 40%, preferably 1 to 10%, particularly preferably 2 to 6%, (D) are present in contents of up to 1%, preferably 0.05 to 0.5%, particularly preferably 0.1 to 0.35%. It is very particularly preferred if the monomers (A):(B) are present in mass ratios of from 1:2 to 2:1. It is very particularly preferred if the polymer is selected from example 22, 24, 25, 28, 35, 37, 40 or 52. The invention also encompasses a thickened preparation comprising a polymer as claimed in any one of the preceding claims. It is particularly preferred if the use concentration of the polymer for thickening aqueous, preferably surfactant-containing aqueous, preparations is 2 to 3%. As a result, the preparation becomes transparent at pH values <6.5 and has a viscosity of at least 3000 mPa·s, which means that added suspended substances do not settle out, possible suspended substances being beads, pigments or air bubbles. It is particularly preferred if the preparations according to the invention are a health product, cleaning product, household product, shower gel, paint, inks, dispersant, antisettling agent, concrete and cement additive, coatings, medicinal product, cosmetic product or dermatological product. The invention also encompasses the use of a polymer according to the invention as thickener, emulsifier, dispersant or consistency regulator.

The preparations—if they are gel-like preparations with yield point—are advantageously designed such that they have a yield point of 0.5-20 Pa, preferably 1-6 Pa.

The yield point is considered to be the critical shear stress of the flow curve. It can be ascertained according to the invention as follows:

The flow curve is measured on a shear-stress-controlled rheometer at 25° C.±1° C. with 20 mm plate/plate geometry with a gap between 0.8 mm and 1.2 mm, with charging being carried out in a structure-preserving manner. A suitable constant shear stress gradient is pregiven and, before the test, a corresponding structure recovery time is observed and the critical shear stress at the maximum of the flow curve is given.

Advantageously, the preparations are designed such that they have a tan δ of 0.05-0.6, preferably 0.1-0.5.

According to the invention, tan δ is understood as meaning the quotient of the loss modulus and the storage modulus. The tan δ is ascertained as follows:

Loss and storage moduli are measured by a dynamic frequency test on a shear-stress-controlled rheometer at 40° C.±1° C. with 20 mm plate/plate geometry with a gap between 0.8 mm and 1.2 mm, charging being carried out in a structure-preserving manner. The frequency test is carried out according to the prior art with an appropriate structure recovery time before the test, and the tan δ in the frequency range between 0.05 rad/s and 3.0 rad/s is quoted, preferably between 0.08 rad/s and 1.0 rad/s.

The preparations are advantageously designed such that, at pH<6.2, they have a turbidity value of NTU (Nephelometric Turbidity Unit)<20. The turbidity value is measured using a turbidity measuring device, with distilled water having a value of NTU=0 serving as standard.

It is also in accordance with the invention if not water, but other polar liquids are thickened by polymers according to the invention. In particular, alcohols, glycols, polyols, amines and organic acids such as for example acrylic acid can be thickened.

The use of polymers according to the invention as emulsifier is also in accordance with the invention. In this way, creams and lotions can be provided.

The polymers are also suitable as dispersants and antisettling agents.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Examples

Synthesis of the Copolymers

The examples below aim to illustrate the present invention without limiting it. The preparation of the examples takes place in accordance with the method described below, the type and amounts of the monomers, chain-transfer agents and protective colloids each used as starting components being summarized in Table 2. Parts and percentages refer to the weight.

Example 1

	Monomer phase
	Methacrylic acid	37.000 parts
	Ethyl acrylate	51.800 parts
	Octadecyl acrylate	5.000 parts
	Emulsogen R307	6.000 parts
	Trimethylolpropane triacrylate	0.300 parts
	Water phase
	Water	33.060 parts
	Sodium lauryl sulfate	0.984 parts
	Reaction vessel
	Water	173.146 parts
	Sodium lauryl sulfate	0.300 parts
	Initiator phase A
	Water	1.911 parts
	Ammonium persulfate	0.069 parts
	Initiator phase B
	Water	2.909 parts
	Ammonium persulfate	0.021 parts

The reaction vessel, which is equipped with stirrer, reflux condenser, nitrogen feed, dosing device and internal thermometer, is charged with 173.146 parts of water and 0.300 parts of sodium lauryl sulfate. The mixture is heated to 82° C. with stirring and under a nitrogen atmosphere.

The monomer mixture is prepared in a second stirred vessel which is equipped with stirrer and nitrogen feed. For this purpose, the monomer phase with 37.000 parts methacrylic acid, 51.800 parts ethyl acrylate, 5.000 parts octadecyl acrylate, 6.000 parts Emulsogen R307 and 0.300 parts trimethylpropane triacrylate is introduced, and into this is mixed the water phase with 33.060 parts water and 0.984 parts sodium lauryl sulfate with stirring and under a nitrogen atmosphere.

As soon as a temperature of 82° C. is reached in the reaction vessel, an initiator phase A, consisting of 0.069 parts ammonium persulfate and 1.911 parts of water, is added and the monomer mixture is metered in uniformly at 85-88° C. over the course of 30 minutes. Then, an initiator phase B, consisting of 0.021 parts ammonium persulfate and 2.909 parts water, is added and then the reaction mixture is post-polymerized for a further 4 hours at 90° C. before being cooled to <40° C.

Examples 2-52

The examples below (Table 1) are prepared analogously to Example 1. In most examples, sodium lauryl sulfate was used as emulsifier. In a departure from this, Examples 5 and 11 were prepared from a combination of sodium lauryl sulfate and ethoxylated isotridecyl alcohol (Genapol X1005, Clamant), and Example 10 was prepared with isotridecyl alcohol (Genapol X1005, Clamant).

Abbreviations

• MAA Methacrylic acid
• EA Ethyl acrylate
• LA Lauryl acrylate
• ODA Octadecyl acrylate
• S20W Bisomer® S20W (Cognis)
  • Methoxypolyethylene glycol methacrylate (EO 45 mol)
• M5010 Maxemul® 5010 (Croda)
  • C₁₂H₂₃HCCH(C₂H₄O₂₅CH₃
• R307 Emulsogen® R307 (Clariant)
  • EO/PO 30 1,4-butanediol vinyl ether (EO/PO 30 mol)
• RAL307 Emulsogen® RAL307 (Clariant)
  • Allylpolyalkylene glycol ether (EO 30 mol)
• R208 Emulsogen® R208 (Clariant)
  • 1,4-Butanediol vinyl ether (EO/PO 25 mol)
• A11/1800 Polyglycol A11/1800 (Clariant)
  • Allylpolyalkylene glycol ether (EO 20 mol, PO 20 mol)
• R500 Polyglycol R500 (Clariant)
  • Vinylpolyalkylene glycol ether (EO 9 mol)
• R1100 Polyglycol R1100 (Clariant)
  • Vinylpolyalkylene glycol ether (EO 20 mol)
• R2000 Polyglycol R2000 (Clariant)
  • Vinylpolyalkylene glycol ether (EO 40 mol)
• AM 20/20 Polyglycol AM 20/20 (Clariant)
  • Polyalkylene glycol allyl methyl ether (EO 20 mol, PO 20 mol)
• AB 1500 Polyglycol AB1500 (Clariant)
  • Polypropylene glycol allyl butyl ether (PO 25 mol)
• AB/25-8 Polyglycol AB/25-8 (Clariant)
  • Polyalkylene glycol allyl butyl ether (EO 25 mol, PO 8 mol)
• A31/1600 Polyglycol A31/1600 (Clariant)
  • Polyalkylene glycol allyl ether (EO 25 mol, PO 8 mol)
• A 10 R Pluriol® A10R (BASF)
  • Allyl alcohol alkoxylates
• A 111 R Pluriol® AMR (BASF)
  • Allyl alcohol alkoxylates
• SPE RALU®MER SPE (Raschig)
  • Dimethyl[2-[(2-methyl-1-oxoallyl)oxy]ethyl](3-sulfopropyl)ammonium hydroxide
• SPM RALU®MER SPM (Raschig)
  • Potassium 3-sulfopropylmethacrylate
• SPP RALU®MER SPP (Raschig)
  • Dimethyl[3-[(2-methyl-1-oxoallyl)amino]propyl]-3-sulfopropylammonium hydroxide
• HMP Bisomer® HMP (Cognis)
  • Monoester of maleic acid and C16-18 fatty alcohol
• KH-10 Hitenol® KH-10 (Dai-Ichi Kogyo Seiyaku)
  • Ammonium polyoxyalkylene-1-(allyloxymethyl)alkyl ether sulfate

• BC-10 Hitenol® BC-10 (Dai-Ichi Kogyo Seiyaku)
  • Ammonium nonylphenol polyoxyethylene alkyl ether sulfate

• BEM Behenyl ethylene glycol-1100 methacrylate
• TMPTA Trimethylolpropane triacrylate
• TMPTMA Trimethylolpropane trimethacrylate
• IMP Isooctyl 3-mercaptopropionate
• AMHEC Tylose AM H40 YP2 (SE Tylose)
  • Allyl-modified hydroxyethylcellulose

TABLE 1
Examples 1-52

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27
MAA	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37	37
EA	51.	53.	53.	53.	51.	53.	53.	53.	53.	53.	53.	47.	53.	53.	53.	53.	51.	51.	51.6	53.	53.	51.	53.	52.	54.	33.	56.
ODA	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5	5
LA				2	2
S20W		2						2	2
M5010		2	2		2	2		2		2	2												2
R307	6		2	2	2	2	4		2	2	2	10	2	2	2	2	6	6	6	2	2
RAL307																						6	2
R208																										24
A11/18																								5.4
R500
R1100																									2.9
R2000
AM
AB
AB/25-8
A31/16
A 10 R																											1.7
A 111 R
SPE													2
SPM														2
SPP															2
HMP																2
KH-10																				2
BC-10																					2
BEM
TMPTA	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.5	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3		0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3
TMPTM																	0.3
IMP																			0.15
AMHEC																		0.0

Ex.	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51	52
MAA	37	37	37	37	37	37	37	37	28.	45.	37	37	37	37	37	37	37	37	37	37	37	37	47.	47.	37
EA	52.	52.	52.	51.	51.	53.	52.	53.1	60.	44	54.	49.	57.	51.8	49.	55.	57.	52.	52.2	52.5	56.	52.	46.	46.	52.
ODA	5	5	5	5	5	5	5	5	5	5	2.5	7.5		5	5	5	5	5	5	5	5	5			5
LA
S20W		5.4
M5010
R307
RAL307
R208
A11/180			5.4	5.4	5.4				5.4	5.4	5.4	5.4	5.4		8.1	2.7		5.4	5.4	5.4				5.4	5.4
R500																					1.4
R1100
R2000																						5.4
AM							5.4
AB						3.9
AB/25-8								4.63
A31/160														5.94
A 10 R
A 111 R	5.4																						5.4
SPE
SPM
SPP
HMP
KH-10
BC-10
BEM																									5
TMPTA	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3		0.45	0.15	0.3	0.3	0.3	0.3	0.3
TMPTM
IMP				0.1	0.1
AMHEC			0.1	0.1

TABLE 2
Results for polymer emulsions

Example	pH value	Particle size* in nm

1	2.48	108
2	2.47	103
3	n.d.	n.d.
4	n.d.	n.d.
5	n.d.	n.d.
6	n.d.	n.d.
7	n.d.	n.d.
8	n.d.	n.d.
9	n.d.	n.d.
10	n.d.	n.d.
11	n.d.	n.d.
12	n.d.	n.d.
14	2.57	102
14	2.62	129
15	3.13	95
16	2.14	186
17	2.53	88
18	2.52	107
19	2.51	101
20	2.53	79
21	2.54	79
22	2.50	96
23	2.52	89
24	2.55	87
25	2.47	111
26	2.67	165
27	2.76	89
28	2.50	87
29	2.56	103
30	2.58	87
31	2.57	95
32	2.48	79
33	2.30	104
34	2.37	96
35	2.46	85
36	2.36	85
37	2.46	113
38	2.39	89
39	2.37	96
40	2.38	94
41	2.65	85
42	2.32	103
43	2.42	91
44	2.39	90
45	2.36	87
46	2.42	101
47	2.34	84
48	2.40	106
49	2.40	123
50	2.69	100
51	2.46	99
52	2.50	124
*The particle size in the polymer emulsion is determined using dynamic light scattering (DLS) in a dilute aqueous sample of the emulsion at 25° C. ± 1° C.

Example 53

The preparation below is intended to illustrate the present invention without limiting it. Unless stated otherwise, all quantitative data, fractions and percentages are based on the weight and the total amount or on the total weight of the preparation.

The polymer according to the invention is diluted with some of the water phase and added to the surfactant phase with stirring. The other formulation constituents apart from NaOH and the suspended bodies are then added with stirring. After the pH has been adjusted, the suspended bodies are stirred into the finished gel base with as little shear as possible.

TABLE 3
Preparation shower gel

	Sodium laureth sulfate	6.50
	Cocoamidopropylbetaine	4.60
	Sodium cocoyl glutamate	0.50
	Polymer	2.25
	PEG-40 hydrogenated castor oil	0.80
	PEG-7 glyceryl cocoate	1.75
	Pigments	q.s.
	NaOH	q.s.
	Perfume	q.s.
	Water	ad 100

TABLE 4
Results for preparation shower gel

	Example	tan δ	Viscosity in mPas	pH of shower gel
	1	0.30	3544	6.19
	2	0.29	2600	6.21
	3*	0.89	2605	6.15
	4*	8.58	1977	6.18
	5*	1.89	2014	6.15
	6*	0.59	2234	6.20
	7*	1.56	1967	6.18
	8*	5.03	1548	6.19
	9*	1.54	2043	6.18
	10*	n.d.	n.d.	n.d.
	11*	n.d.	n.d.	n.d.
	12*	8.14	1465	6.11
	13	0.32	2404	6.18
	14	4.54	2055	6.25
	15	0.70	1964	6.18
	16	0.27	2423	6.15
	17	3.57	3356	6.18
	18	0.31	2092	6.20
	19	1.12	1998	6.18
	20	1.92	2754	6.17
	21	4.42	2090	6.23
	22	0.37	3118	6.23
	23	0.35	3089	6.22
	24	0.17	3409	6.20
	25	0.19	4100	6.22
	26	4.42	3592	5.86
	27	0.15	2967	6.17
	28	0.14	3301	6.15
	29	2.58	2442	6.18
	30	2.54	1941	6.21
	31	0.52	2233	6.15
	32	1.83	2752	6.15
	33	0.79	2953	6.20
	34	0.83	2208	6.21
	35	0.24	3501	6.20
	36	0.34	2833	6.38
	37	0.23	3432	5.91
	38	0.20	3262	6.18
	38	0.26	3580	6.11
	40	0.16	4120	6.25
	41	0.39	3317	6.19
	42	0.17	3230	6.15
	43	0.25	3690	6.15
	44	0.22	4167	6.28
	45	5.97	3196	5.97
	46	0.60	2385	6.14
	47	0.26	4349	6.17
	48	0.22	4073	6.29
	49	0.42	3313	6.09
	50	0.37	3827	5.87
	51	0.83	3580	5.93
	52	0.14	7344	6.07
	*The examples were prepared without perfume in the shower gel.

The viscosity of the preparations is measured on a rheometer at 25° C.±1° C. with 40 mm cone/plate geometry (1° cone angle) with a gap of 0.03 mm, charging being carried out in a structure-preserving manner. A suitable constant shear rate time ramp is pregiven and a corresponding structure recovery time is observed before the test. The viscosity is given for a shear rate of 10 s⁻¹.

Example 54

It has surprisingly been found that the morphology of the polymers produced by a rapid dosing of the monomer mixture is advantageous within the context of the present invention. Table 4 shows the various properties of two polymers when the dosing time is varied. The dosing time is preferably 40 minutes and particularly preferably 30 minutes.

TABLE 5
Dosing time and results

	Polymer	Dosing time	tan δ	Viscosity in mPas

	Example 35	30 minutes	0.24	3501
	Example 35	40 minutes	0.21	4114
	Example 35	50 minutes	0.49	4056
	Example 35	60 minutes	1.45	3585
	Example 24	30 minutes	0.17	3409
	Example 24	50 minutes	24.26	1805

Example 55

The polymers according to the invention must have adequate storage stability. For this purpose, a shower gel according to Example 53 was produced again after one year from Examples 1, 22, 24, 25 and 28. It is found that the polymers according to the invention are also advantageous after prolonged storage at room temperature.

TABLE 6
Results of storage stability

after 24 h

after storage

		Viscosity in			Viscosity in
Polymer	tan δ	mPas	Time	tan δ	mPas
Example 1	0.30	3544	15 months	0.24	4285
Example 22	0.37	3118	13 months	0.29	4247
Example 24	0.17	3409	13 months	0.20	4083
Example 25	0.19	4100	13 months	0.22	4823
Example 28	0.14	3301	10 months	0.20	3754

Example 56

Compared to other polymers, the polymers according to the invention overcome deficiencies in the prior art compared to other polymers.

In order to illustrate this, a shower gel according to Example 53 was prepared in each case from Examples 24, 37 and Carbopol® AQUA SF-1 (Lubrizol).

TABLE 7
Results compared to AQUA SF-1

	Example 24	Example 37	Carbopol ® AQUA SF-1

tan δ	0.17	0.23	0.42
Viscosity in mPas	3409	3432	3834
Yield point in Pa	3.6	3.4	3.3
pH	6.20	5.91	6.45
Turbidity in NTU	8	9	18
			(58 at pH 6.20)

At a lower pH than AQUA SF-1, the polymers according to the invention have a better tan δ and a lower turbidity. Turbidity values of <10 are comparable with spring water. Upon adjusting a preparation containing AQUA SF-1 to a lower pH value, e.g.: 6.20, the preparation is distinctly perceptibly turbid (NTU=58).