DE3240775A1 - STABILIZERS FOR EMULSION POLYMERISATION - Google Patents

Description

The invention relates to stabilizers and their use in the emulsion polymerization of olefinic monomers

for the formation of stable and low-flocculation latices and 5

especially those latices that are used commercially as self-adhesive or non-self-adhesive adhesives or pressure-sensitive adhesives are usable. The invention also relates to a method for carrying out the emulsion polymerization and to pressure-sensitive adhesives or adhesives containing a latex produced according to the invention.

The use of surfactants in emulsion polymerization leads to inconveniences due to the tendency of these surfactants to migrate and also because of the Water sensitivity imparted to the polymer by such surfactants. Known emulsion stabilizer systems contain compounds of the monomeric type, i.e. compounds having at least one olefinic bond, the copolymerize with a primary polymerizable monomer can and thereby be incorporated into the main chain of the polymer. Such stabilizers are for example described in U.S. Patents 4,029,658, 3,893,166, 3,925,442, and 3,483,155; this stabilizer must be in

usually used in a polymerization system, 25

which must be essentially free of electrolytes in order to avoid flocculation or the formation of coagulate. As a result, however, the use of polymerization catalysts, which are otherwise more favorable, is generally ruled out Polymerization rates and polymer structures were revealed.

Numerous latices suitable as adhesives have to withstand be resistant to higher temperatures and moisture, which is why their stability and properties are considered are extremely important to water sensitivity. *

The degree of water vapor transmission rate (WVTR) that the Capacity of the adhesive to let through or penetrate determined by moisture, is also relevant to that permanent adhesion in a damp environment. Further, it is desirable that the polymerization have a high conversion of the monomer of at least 80 or »90% and more allows. The previously proposed for such purposes Stabilizers are inadequate for one or the other of the criteria mentioned above.

US Pat. No. 4,224,455 discloses emulsifiers or surfactants as a reaction participant in the emulsion polymerization of numerous olefinic monomers, such as acrylates, Acrylic acid, acrylonitrile, styrene, butadiene, vinyl acetate and

-j5 like, for the production of homopolymers and copolymers, known from graft and block polymers. These emulsion polymers can be used as paper coatings and for paints are used and show adhesion and abrasion resistance or abrasion resistance. Known emulsifiers are sulfonated half-ester reaction products of maleic anhydride and of an alkoxylated arylol with an alkyl radical substituted on the nucleus.

The present invention is based on the surprising finding that stable and low-flocculation latexes with good shear stress can be produced, which can be used as pressure-sensitive adhesives or as non-self-adhesive, if non-sulfonated monomeric emulsion stabilizers, the half-esters of cc, ß- ethylenically unsaturated dicarboxylic acids and / or their anhydrides.

The invention has the task of stabilizers or an emulsion polymerization process using these stabilizers and the resulting latex

To create polymers, the difficulties mentioned above being eliminated or at least substantially reduced will. Stabilizers for emulsion polymerization should also be used of monomeric acrylates in general - are created with which stable and low-flocculation Latices with good shear force, chemical stability and improved water vapor permeability can be obtained. A further object of the present invention is to provide stabilizers for emulsion polymerizations with which Electrolytes can be used as polymerization catalysts without adverse effects occurring. Furthermore, stabilizers should be proposed for these purposes that show no tendency to act as Adversely affecting latex products that can be used with adhesive or restricting their effect. Ultimately, should 15th

. according to the invention latex products are proposed which are suitable as adhesives for numerous commercial purposes.

These objects are achieved according to the invention by a Stabilizer for emulsion polymerization, which featured is by monomeric, polymerizable half-esters of c (-ethylenically unsaturated dicarboxylic acids and nonionic Ethoxylates of the general formula

- C * - COOR ₄

in the

// η ι

R is a CH-, (C- to C -alkyl) -C- or CH = C-

Group represents, being in the first and second

*
If the group R. is linked to C by an olefinically unsaturated bond, while in the latter case C is a> CH group,

Rp is a hydrogen atom or a C to C alkyl group and

R_ and R ₄ each represent a hydrogen atom or a salt-forming group or a R -Z- (CH "CH" O) group with the proviso that one of the two radicals R_ or R is a hydrogen atom or a salt-forming group and the other radical is a R represents -Z- (CH CH O) group,

O el fL X

where R _{K is} a hydrophobic radical, namely an alkyl group with 8 to 30 C atoms, a phenyl group or an alkylphenyl group with one to three C to C alkyl groups, which is connected via a link Z, which is an oxygen, sulfur or nitrogen atom is linked to the ethoxy chain, and where χ is an integer of 4

to 10 is.

In detail, it should be noted that for the invention General purpose stabilizers for the emulsion polymerization of ^ -monoethylenically unsaturated monomer- ^ systems containing acrylic type monomers such as acrylates, acrylonitrile and the like, as well Vinyl type monomers such as vinyl chloride, vinyl acetate, vinylidene chloride, styrene and the like are proposed which Half esters of tf-ethylenically unsaturated dicarboxylic acids or whose anhydrides are with nonionic, hydroxyl-containing surfactants. Dicarboxylic acids such as Maleic acid, itaconic acid, citraconic acid and glutaconic acid, although generally any dicarboxylic acid is used can, which contains at least one copolymerizable olefinic bond (with an acrylic or vinyl radical), as well as the Anhydrides of the dicarboxylic acids mentioned. Preferably the olefinic bond is adjacent to one of the Carboxyl groups, particularly preferred compounds being the

olefinic bond adjacent to the two carboxyl-35s

have residues, such as in maleic acid or Citraconic acid. Although itaconic acid is olefinic Bond not adjacent to both carboxyl residues is, this is also particularly preferred because the

Itaconic acid in the vicinity of the one carboxyl group 5

contains a reactive vinyl radical. In general, the Dicarboxylic acids from 2 to 10 carbon atoms and preferably up to 4 carbon atoms in addition to the carbon atoms of the two carboxyl radicals.

The nonionic reactant generally has the formula R ₅ -Z- (CH ₂ CH ₂ O) _x -H

in which R is a hydrophobic residue, which via a connection

member Z, which is an oxygen, nitrogen or sulfur atom

15 .- -

is linked to the ethenoxy chain, and in the χ one is an integer from 4 to 10. The preferred hydrophobic radicals R are C to C alcohol groups, a phenyl group or an alkylene group of one to three and preferably 1 to 2 alkyl radicals with 4 to 18 and preferably 4 to 9 carbon atoms, such as the diisobutylphenyl, Nonylphenyl and dinonylphenyl groups.

The stabilizer according to the invention with the above and in 25th

Claim 1 given general formula is an ethylenically unsaturated, monomeric half-ester in the form of a Acid (R_ or R. = hydrogen) or a salt (R_ or Usually a salt-forming group, for example an alkali metal cation, an ammonium ion or an amine group) is present.

Furthermore, according to the invention, there is a method of production the stabilizers or those suitable as stabilizers

Connections suggested. 35

The invention also relates to a process for carrying out the emulsion polymerization of such monomeric systems, characterized in that the monomers with the stabilizer according to claims 1 to 3 and an effective amount of a suitable polymerization catalyst at a temperature of about 5 to 80 C in an aqueous medium at a pH above about 4 to give a stable latex product having 45 to 55 wt.% solids, that the weight ratio of monomers to stabilizer is about 50: 1 to 10: 1 and that the monomers, the Stabilizer and the catalyst are added to the aqueous medium in the form of an aqueous pre-emulsion, a first portion, which makes up about 20% by weight of the total amount of the pre-emulsion, is added first and the remaining portion is only added when the polymerization reaction reaches an exothermic initial stage has, the pH being maintained during the polymerization wi approx.

For example, the method according to the invention can be used in Temperatures of 50 to 70 C in an aqueous medium a pH of 4 to 6 adjusted depending on the type of monomer used, whereby the above mentioned monomers and the stabilizer in the presence of an effective amount of a polymerization catalyst to form a Reacts stable latex, which has about 45 to 55% by weight solids, the weight ratio of monomer to stabilizer is in the range of about 50: 1 to 10: 1 and furthermore wherein the monomer, the stabilizer and the catalyst be added to the aqueous medium in the form of an aqueous pre-emulsion, a first portion of which consists of to about 20% of the total amount of the pre-emulsion is initially added and the remainder is added when the polymerization reaction has reached an initially exothermic state, with the temperature and pH value im

The course of the polymerization reaction is maintained

The invention also relates to stable latex products with good adhesive properties, which are advantageous as self-adhesive Adhesives, binding adhesive latices and the like for are suitable for commercial purposes.

The stabilizer compounds are expediently prepared by reacting the (& , ß-unsaturated dicarboxylic acid or the corresponding acid anhydride with a nonionic emulsifier of the formula R -Z- (CH CH O) H, where R, Z and χ have the meanings given above takes place in bulk in a solvent-free system at temperatures of 80 to 120 ° C., and the molar ratio of nonionic emulsifier to acid or anhydride is in the range from 0.5: 1 to 1: 1. An at least substantial conversion of the reactants to the half-ester can be achieved in Production scale can be achieved in periods of 5 to 8 hours.

Suitable nonionic emulsifier rectants for forming the half esters include the following commercially available Products: Triton X-45 from Röhm &. Haas, which is an octylphenol with a pentaethoxy radical, hereinafter referred to as EOP-5; IGEPAL CO-530 of GAF, the one Contains nonylphenol with a content of hexaethoxy radicals and is referred to below as ENP-6; IGEPAL CO-630 the GAF, which contains a nonylphenyl containing a nonethoxy group and hereinafter referred to as ENP-9 will; TERGITOL NP-14 from Union Carbide, which contains a nonylphenol containing a tetraethoxy group and hereinafter referred to as ENP-4, as well as TERGITOL 15-S-5 from Union Carbide, which has a linear C ..- to C.,. Contains alcohol containing a pentaethoxy group

35 and hereinafter referred to as ELA-5.

O 6 "- _ O β _ β O -4

The stabilizers can be used as ethoxylated monomeric emulsion stabilizers, hereinafter abbreviated to EMES, j where the term "monomer" is justified, since, as is to be explained, substantial proportions of the same via activation of the olefinic double bond the formation of the polymer chain during emulsion polymerization of the monomeric aeryl system. The built-in EMES connection is obviously called Unit built into the polymer chain or on others Connected to the polymer via a stable bond. This assessment is made by a liquid chromatographic Analysis of the obtained latex confirmed.

Examples 1 to 10

Examples of the synthesis of EMES compounds by specifying the reaction conditions, the actual and theoretical Yields result from the following table 1. The syntheses are based on equimolar ratios of nonionic emulsifier and maleic anhydride, with the exception of Examples 1 to 4, in which a ratio of 0.57: 1 was observed. Although the following examples were performed with maleic anhydride, other anhydrides of the type described above are also used

25 and equivalent results can be obtained.

* te m 9

not Table 1 Reaction Temp. Theoretical yield more ionic time in in ⁶ C Yield in found example Emulsifier hours 80-100 Liter meq./g 2.67 No. ENP-9 5 90 3.17 2.77 1 ENP-9 7th 118 3.17 3.53 2 ENP-9 6.5 100 3.17 3.00 3 ENP-9 8th 100 3.17 1.72 4th ENP-9 7th 80 1.40 1.96 5 ENP-4 7th 100 2.02 1.63 6th EOP-5 7th 95-100 1.91 1.83 7th ELA-5 6th 95-105 1.93 2.02 8th ELA-5 7th 95-100 1.93 1.84 9 ENP-6 7th 1.72 10

In all cases the product yield corresponded to at least 80% conversion of the reactants and in most cases was at least 90 %. In those cases in which the values found are above the theoretically calculated yields, the difference can presumably be explained by the stoichiometry of the reactants, since the molecular weight of the nonionic reactants is also based on a published average value and therefore not exactly the reality in the special case is equivalent to.

The stabilizing effect and other beneficial effects, which can be ascribed to the EMES are generally more diverse in connection with emulsion polymerization Acrylic monomers, including mixtures of these

with copolymerizable polar monomers which contain a single double bond, namely an ol , ß-monoolefinically unsaturated bond. The acrylic monomers have the general formula:

^R 2

CH ₂ = C - COOR ₃

in which R_ denotes hydrogen or a methyl radical and R "denotes an alkyl radical having 1 to 14, preferably 1 to 8, carbon atoms. If R "is in the higher range of, for example, 8 carbon atoms or more, at least 2 to about 20 % of the selected acrylic monomers should preferably have an R_ value below 4 in order to ensure the cohesion

15 y.

to improve strength of the polymer obtained. Examples of suitable acrylic monomers include 2-ethylhexyl acrylate (2-EHA), butyl acrylate (BWA), methyl methacrylate (MMA) and Ethyl acrylate (EA).

Polar monomers that are copolymerizable therewith are, depending on the conditions used, in the Emulsion polymerization, for example acrylic acid (AA), " Methacrylic acid (MAA), vinyl acetate (VA), acrylonitrile (AN), Ν, Ν-dimethylacrylamide (NNDMA) and the reaction product of Hydroxypropyl acrylate and succinic anhydride (HPASA) and the like acrylic monomers concerned alone or in admixture with other acrylic comonomers and / or polar comonomers can be used. The choice of monomers understandably affects the serviceability of the end product. With regard to adhesives, monomers are selected that typically give sticky and adhesive polymers and which, if appropriate, are supplemented by monomers,

which give the latex a cohesive strength, like 35

for example styrene, methyl acrylate or methyl methacrylate. This is particularly important if you want to produce pressure-sensitive adhesives, ie self-adhesive adhesives. In the latter case, it is advantageous to use larger proportions of 2-ethylhexyl acrylate, for example, in amounts which make up at least about 65% by weight of the total acrylic monomers and polar monomers with which the polymerization reactor is charged. Mixtures of 2-ethylhexyl acrylates with up to, for example, 20% butyl acrylate, 5 % methyl methacrylate and / or 5 % Ν, Ν-dimethylacrylamide are particularly effective for the production of latices that can be used as pressure-sensitive adhesives, e.g. by coating a vinyl film or Dexter Paper.

Other suitable monomers include vinyl chloride, vinylidene chloride, conjugated dienes such as 1,3-butadiene, vinyl-substituted aromatics such as styrene. In this regard, particularly effective "no pressure" monomer systems contain butadiene alone or with styrene and / or acrylonitrile. The last-mentioned butadiene systems can be converted into pressure-sensitive, self-adhesive products if suitable known adhesives are mixed in, such as terpene resins and rosin ester resins, as well as those of the polymeric type based on polymers of cC -methylstyrene, vinyltoluene and styrene or other known polymers.

Likewise, by suitable selection of the monomers and also of the EMES compound, polymeric adhesive latexes of the non-self-adhesive type can be obtained, as will be explained in detail below. In these cases, the 2-ethylhexyl acrylate is replaced by ethyl acrylate as the primary monomer and used effectively in combination with relatively large amounts of methyl methacrylate of, for example, up to 30 %, based on the total monomer used.

The EMES stabilizers are of considerable advantage both with regard to the process according to the invention and the product according to the invention obtained when they are used in amounts of from 2 to 10 and preferably from 2.5 to 6 parts per 100 parts of the monomer. The yields of polymer latex correspond to 90 % and higher conversions of the monomeric reactants can be achieved. There is no need to use surface-active emulsifiers, so that the problems of water-IG sensitivity and migration of the surfactants which otherwise arise as a result are avoided

will. The polymeric latices show good shear force and chemical resistance with little or no tendency to phase separation or coagulation despite prolonged standing. The latex is compared with appreciable amounts of electron ■ \ 5 trolyten insensitive and does not coagulate, so that free-radical polymerization catalysts of Persulfattyps can be used. Flocculation is avoided, or at least reduced to a negligible level, provided that the pH ranges are within the stated range. However, the selection of the monomer may result in slight deviations. The latices obtained have a relatively high solids content of the order of 45 to 55% and, when used as adhesives, are not adversely affected by the presence of EMES or other recommended additives or their mode of action is not impaired. The water vapor permeability (WVTR) is very much better in comparison with other stabilized, polymer-forming emulsion systems, so that their usefulness as polymeric latices for adhesives is increased. The EMES compounds can advantageously be used generally in acrylic emulsions to improve the chemical stability, shear strength and the like of the latices obtained, regardless of the intended use for the product.

The preferred addition polymerization catalysts are free radical initiators of the peroxide type, such as tertiary butyl hydroperoxide (TBHP) in 90% solution and preferably in combination with sodium formaldehyde sulfoxylate / iron {II) ammonium sulfate, or alkali persulfates, such as potassium persulfate, which are preferably used in combination with a bisulfate solution such as sodium bisulfate. The necessary The amounts of catalyst are such that they initiate the polymerization, as is generally known. the Selection of the catalyst also depends on the nature of the monomer (s) and the reaction temperature, in order to achieve maximum To achieve results.

Flocculation or coagulation and the like to turn off or reduce, the pH of the polymerization reaction medium must be at pH at least about 4.5, and preferably between about 5 to 7, are maintained for hydrolyzable monomers. at For some monomers, pH values down to 4.2 are also permissible, as Example 38 shows, so that the reference to taking into account a pH value of the aqueous medium of 4.5 of the above must be judged accordingly. The pH value is adjusted with suitable bases, like ammonium hydroxide.

The temperatures for the polymerization reaction are usually kept in a range from 50 to 80 ° C, wherein the individual values must be selected depending on the monomer, the catalyst and EMES. In general, this is done with Peroxide-induced polymerization in a temperature range of 55 to 60 C, while with persulfate catalysts temperatures 60 to 65 C are recommended. In general, however, the temperature range can be from 0 to about 100.degree are suitable known catalysts.

The mixture forming the polymer can contain additives can be added to achieve special effects. For example auxiliary dispersants can be used in small amounts of 0.3-0.8 parts per 100 parts of the monomer Reduction in areas of coagulum and / or viscosity such as that available from Dewey and Almy, Division of W.R. Grace Co. sold products DAXAD 11 that contains the sulfonated reaction product of formaldehyde and naphthalene.

Thickeners can also be used as an adhesive preferably used to increase the viscosity of the latices , whereby in the present case the products ACRYSOL ASE 95 (Rohm & Hass) and 68-710 (Reichold Chemicals,

15 Inc.) are suitable.

In carrying out the polymerization, an aqueous pre-emulsion of the entire charge of monomeric catalyst and EMES is formed with about 30 to 50 parts of water per 100 parts of monomer. Additional catalyst components, such as the bisulfite and / or the sulfoxylate / iron (II) ammonium sulfate, are not present in the pre-emulsion and are added separately as aqueous solutions. About 10 to 20 % of the pre-emulsion is added to the reaction vessel together with additional water, usually in an amount of 40 to 60 parts per 100 parts of monomer, and further dispersants such as DAXAD-11. The entire charge is heated to a temperature of 50 to 70 ° C. under nitrogen or when purging with nitrogen. The polymerization begins with the addition of 10 to 20% by weight of the cocatalyst solution; After the originally exothermic reaction has ceased, the remainder of the pre-emulsion is preferably added continuously over the remaining period of time for the formation of the latex, which is usually 90 to 120 minutes. When adding the cocatalyst solution, the temperature of the

Maintained reaction medium in the specified range of preferably 50 to 55 ° C, and during the process is the pH to a value of 4.5 by adding NH OH set.

The following examples illustrate the invention Polymerization process that works with both peroxide and is triggered with persulfate. All quantities are based on weight.

Example 11

The following preparation was made:

Parts

2 EHA (SO ₄ game 2 BuA 20th AA ige ) ₂ .6H ₂ O Solution ) EMES from Be 25th H ₂ O DAXAD 11 Fe (NH ₄ ) ₂ SFS TBHP (90%

80 5 13th 00136 2 12th 5 18th 100 Οι- Ο, 0, O,

The monomer, EMES and TBHP were pre-emulsified in 35 parts of water. The reactor was charged with 50 parts of water, DAXAD 11 and, via a funnel, with 10 % of the Voremulsiön. The sulfoxylate / ferrous ammonium sulfate was dissolved in 15 parts by weight of water and added via another funnel. The reaction mixture was heated to 50 ° C. while flushing with nitrogen, and 10% of the sulfoxylate / iron (II) ammonium sulfate was added. After achieving a

ft ·· »ft * *»

- 21 -

The remainder of the pre-emulsion and the cocatalyst solution became exothermic in the course of 90 min. if maintained
added.

Maintaining a temperature of 50 to 55 C continuously

Example 12

The procedure was analogous to Example 11, but the

the following monomer system was used. 10

Parts

2 EHA 80

BuA 10

AA 5

Example 13

Example 12 was repeated except that the following modifications were made:
0.3 parts of K ₀ S ₀ O _{0 were} used as the catalyst

<L d σ

together with the monomers and EMES in 47 parts of water Resulted in pre-emulsion. The polymerization was carried out in which the original reactor charge from the pre-emulsion (10% of the total) and DAXAD 11 to 55 to ° 60 C was heated under a nitrogen purge, with 0.075 Parts of NaHSO ,, in three parts by weight of water were added. Otherwise, the procedure was analogous to Example 12.

In the tests according to Examples 11 to 13, a stable latex with about 50 % solids was obtained, the properties of which are given in Table 2.

•• - ■ -2-2

10

% freer
stabilizer Table 2 Flockunq Conversion example
No. 2.0
1.8 PH value
the latex 0.5
O
O 99+
97
95 11th
12th
13th 6.8
7.1
5.0

The results show that practically complete conversion of the monomer and no flocculation was obtained in the case of the systems with peroxide activator and persulfate activator. This illustrates the performance of the mixtures according to the invention, in particular the resistance to electrolytes, which have little or no adverse effects. Liquid chromatography determined that about 60 % of the EMES was incorporated into the polymeric latex.

When repeating the procedure according to Example 11 total flocculation was achieved in a reaction medium with a pH of 2.

The effects of a modification of the EMES connection a given monomer system result from Examples 14 to 22.

35

BATH ORIGINAL

"-" 23 -

32A0775

Examples 14 to

The procedure was analogous to Example 11, the following monomer system being used.

2 EHA BuA AA

Parts 75 15 5

The tests in the table below produced 5 parts EMES used.

Tabel

example
No. EMES off
example
No. ° /
conversion O/
/O
Flocculation μπ-werL
of latex Fixed proportions Brook fellij
Viscosity
(RVT) eP «j 14th 2 97.7 0 4.9 48.5 1,100 ^S: 15th 2 99.5 0 6.2 49.3 2,650 ^S 16 6th 99.9 1.6 5.6 44.4 12,200 ^b 17th 8th 98.6 0 6.3 49.3 3,500 ^b " 18th 10 96.0 0 6.0 48.0 ' 7,200 ^b; 19th 9 100 0 5.7 50.0 4,120 ^b) 20 ^Φ 9 94.0 1.5 6.2 49.0 3.165 ^C; 21 5 95.4 0.5 6.8 47.6 9,280 ^bl 22nd 7th 95.0 0 5.8 47.5

a) b} c) d)

No.3 spindle a 20 ps No.5 spindle a 20 ps No.2 spindle a 20 ps DAXAD 11 has been omitted

BATH ORIGINAL

It is noteworthy that a flake-free latex in Example 14 was obtained despite a pH value slightly below 5. When the pH value is increased to 6.2 and when comparing the same EMES (Example 15)

an improved conversion of 99.5% versus 97.7 % 5

and an increased solids content of 49.3 % compared to 48.5 % and a higher viscosity of 2650 compared to 1100 cP; However, when Example 14 was repeated at pH 3.3, the flocculation level increased to 35 %. When working analogously to Example 16 with a pH of 4.4, the flocculation rose to 39%.

These values in turn show that it is important to maintain the pH in the specified range to keep the coagulation as low as possible. That explains itself in the first place 5

Line in that the EMES compound becomes more and more water-insoluble at a pH value below about 5, so that relatively unstable polymerization systems are to be expected. the Omission of DAXAD 11 (Example 20) resulted in only a slight increase in flocculation of 1.5% compared to 0. The relatively high latex viscosities are believed to be based due at least in part to the high AA content and latex particle size.

The effect of DAXAD 11 at the recommended pH 25th

and the low EMES concentrations result from the

Examples 23 to 28.

Examples 23 to 28

The procedure was analogous to Example 11, the composition of the monomer and the concentration of DAXAD 11, as indicated in Table 4 below, was modified. In each case an EMES according to Example 9 was used.

Table 4

5 example
No. Parts
DAXAD 11 Parts of monomer
2-EMA BuA AA 19th 5 Parts
EMES PH value Flocculation 23 0.5 75 18th 5 1 8.6 10.7 24 0.5 75 18th 5 2 8.4 0 O 25th O 75 18th 5 2 8.3 4.0 26th 0 74 15.5 5 3 8.1 1.5 27 0.5 75.5 15.5 5 4th 6.8 O 28 ^a > 0.5 75.5 > λ ^ » \, 4- y ■ v r ^ 4th 5.5 O 5 / \ / Q 1 "» C 1 t i m 7K _ 1 _ C

B ^e i all experiments according to Examples 23 to 26 was obtained a latex polymer; however, complete coagulation took place within one week in each case. Nevertheless it can be stated that DAXAD 11 influences flocculation. In the case of some EMES (example 23), the DAXAD 11 obviously has only a minor influence (10.7 % flocculation). If, however, DAXAD 11 is omitted (example 25), a flocculation increase from 0 to 4.0% is obtained in comparison with an otherwise identical composition with 0.5 parts of DAXAD 11 (example 24) which contains only two parts of EMES. At the recommended EMES levels of 4 parts (Examples 27 and 28) a stable, non-flocculating latex is obtained. The experiment according to Example 28 with a 75 l reactor led, compared to Example 27, primarily to latex viscosities with values of 69 cP and 4400 cP. This difference is based on a

the particle size and / or the pH effect differed. the Latices according to Examples 27 and 28 are in terms of conversion and the solids content about the results of to equate previous examples.

The latices according to Examples 11 to 22 and Examples 27 and 28 are suitable as self-adhesive adhesives (pressure-sensitive adhesives). The adhesive strength of this Products can be increased, for example, that methyl methacrylate is used in the monomeric mixture. This is evident from Examples 29 to 34 below.

Examples 29 to

Example 11 was repeated with the difference that with the changes specified in Table 5 below were used. In each case, the EMES was carried out according to the example 9 used in an amount of 5 parts.

Tabel

example
No. Monomer
2-EHA BuA 12.5 r MMA AA % Flok
kung BATH % Fixed
fabrics Conversion
in% pH
value Brookfi
Viscose
(in eP- 29 75 , 5 15 2.5 5 0 48.3 96.6 6.6 5920 30th 72 10 2.5 5 0 48.8 97.6 6.6 5800 31 75 15th 5 5 0 48.8 97.6 6.6 2120 32 70 12.5 5 5 0 49.0 98.0 6.6 9000 33 ^a) 75 15th 2.5 5 0 51.4 100 8.8 34 ^a) 70 5 5 0 51.0 100 8.1 - ORIGINAL 75 1 Reac to COPY H

The Brookfield viscosity was with a spindle number 5 at 20 UpS determined.

In each case a stable latex with good adhesive strength was obtained,
ο

The above examples show the effects of a monomeric system based on 2-ethylhexyl acrylate, butyl acrylate and acrylic acid.

10.

In the following examples, one or more monomers included and the butyl acrylate and / or acrylic acid, as indicated, replaced.

Examples 35 to 39

The latices obtained with modified monomer systems had the following properties shown in Table 6. In Examples 35 and 36, the polymerization was stimulated with peroxide analogously to Example 11, while at Examples 37 to 39 the polymerization with persulfate according to Example 13 was carried out.

In all cases, the monomer used was an EMES according to example 2 used.

COPY BAD ORIGINAL

example

Proportions of monomer

2 EHA
BuA

HPA-SA ^c
AA

Tabel Latex analysis: pH -% flocculation -% conversion

35 7.5

a)

36

10

37 5

38
4.8

b)

39
5

pH - flock. - Umw. • 7, 6- none - 94%

80

15th

pH - flock. 7.0 - none

80

10 10

• Environment pH flock. 96% 4.9 - none

80 10 10

Umw. PH - Flock 99 +% 4.2 - no 76.2 9.5 4.8 4.8

Ambient pH flocking ambient 4.3 - 5.0 - 92.5%

80

10

a) Peroxide-initiated polymerisation process according to example

b) Persulfate-initiated polymerization process according to example

c) reaction product of hydroxypropyl acrylate and succinic anhydride

d) Ν, Ν-dimethylacrylamide

Q Φ * ^ T "* eC" SC7 - · ffi · # fc. ·

In Example 38, despite a pH of 4.2, no flocculation was noticed, which shows that the use of such a monomeric system is relevant with regard to the establishment of pH limits. For comparison, reference is made to 65jej.sp.ie-1, in which the flocculation increased from 1.6 to 39% with a corresponding change in pH from 5.6 to 4.4. Of course, the EMES catalysts used and the composition of the monomer differed from the examples to be compared. A comparison with the example _in FIG. 39 also shows flocculation of 5 % at a pH of 4.3.

The experiments according to Examples 38 and 39 were carried out with persulfate carried out as a polymerization stimulator. The received Latices were stable and stood out for the above specified properties.

The adhesive properties of the various above mentioned Latices were made by coating a vinyl film and by Definitely Dexter paper. The samples produced in the reactor were knife-coated onto the vinyl film made from the emulsion. The test results are shown in Table 7 below summarized.

Thickness in
Mils Sticky
speed Table 7 liability
of steel
(oz / in) liability
on the pad
(oz / in) Fast
liability
(oz / in) T-peel test
(oz / in) 0.8 4.6 Self-adhesive properties on vinyl film 17th __ 10 10 Latex acc.
example
No. 1.8 5.2 sample
Sticky
ability (g) 19th 17th 14th 14th 1.1 5.0 358 18th 15 ' 17th 13th 16 1.6 6.1 300 22nd 18th 19th 12th 17th 1.3 ' 5.4 446 21 15th 17th 10 18th 1.4 4.9 436 17th 9 15th 10 20th 1.4 3.1 448 26th 23 22nd 17th 21, 1.0 5.7 314 13th 12th 11th 8th 22nd 1.4 5.6 388 10 9 10 6th 27 1.4 5.8 374 41 16 14th * - 27 ^a 1.6 5.2 368 18th 18th 14th 14th 29 1.3 5.2 368 18th 18th 12th 29 ^a 1.0 6.0 298 20th 19th 15th - 30th 1.5 5.2 324 19th 15th 12th - 31 1.5 4.9 348 17th 19th 15th 11th 32 236 32 ^a 314

{> * β Q & β · - A β * *

Adhesive properties on Dexter paper

example
No. Coating
(g / yd) WVTR b)
Porosity in / 5 min. 14th 37.9 59.4 16 37.8 109 0.39 17th 34.0 67.8 0.7 18th 52.6 60 0.23 20th 32.3 120 1.08 21 . 35.3 71.5 0.03 22nd 39.2 104 . 1.48 27
₂₇ a) 41.1
42.5 77.5
83.5 0.25
0.53 29 41.0 77.4 0.08 30th 38.2 76.1 0.11 31 39.1 80 0.38 32 53.9 55.7 0.04 32 ^a) 57.3 55.7 0.21

^a) 75 -! - reactor
'Heavy cylinder

The above samples were tested using standard procedures. The porosity was determined with a Gurley instrument with a heavy cylinder. The standard test became modified due to the relatively non-porous nature of the coated paper. After the cylinder was released the movement of the cylinder measured in inches over 5 minutes. In most cases the cylinder couldn't reach the zero calibration mark, which is usually a Indicates non-porosity. The latex according to Example 16 showed a considerable increase in the WVTR value of 109 g / 100

2
in / 24 hours. This corresponds essentially to earlier experiments carried out according to Example 6 with a copolymer of 2 EHA / BuA / AA / EMES in the ratio 80/13/2/5

were, the measured WVTR value 83g / 100 in / 24 hours.

fraud. The WVTR values fluctuate somewhat and naturally hang

on the porosity of the coated paper. Samples

were mainly non-porous.

The data suggest that the products with 4 moles of ethoxyl-EMES structure and possibly also with 5 moles of ethoxyl-EMES structure more effective with regard to water vapor transport are. Assuming that the EMES has been incorporated into the polymer to the same extent, the Values indicate that a distribution of "short" ethoxy units along the polymer chain appears to be related to the Water vapor transport are more effective than those of "longer" Ethoxy units.

A sample of the Dexter paper made with a latex according to Example 17 was coated, was examined with regard to water transport by adding red-colored water applied the adhesive surface. The sample was placed on the rim of a beaker during the test period. It was found that within 15 to 20 min. the water

was transported through the sample, the paper fibers 35

in which the transport pattern were most stained. Of the

- 33 - ■■■ -., -.

The area of strongest staining was then determined in terms of Permeability using an air densitometer with evaluated the heavy cylinder. No air permeation was observed in 5 minutes, indicating that an against Air impermeable product was present. This was found, albeit a relatively lower one for this sample WVTR was found to be 67.8. It is possible, · that fibers that extended over the adhesive layer or Out of this protruding, are able to water due - ^ O to conduct the capillary action through the adhesive tape. Since the Coatings obtained by pouring the latex directly onto the Dexter paper would look on the surface do not accept uncoated fibers.

-55 Table 7 shows that the adhesive properties of the various 2-EHA / BuA / MMA / AA / EMES copolymers are essentially equivalent to one another and do not depend on the EMES used. Furthermore, the addition of MMA to the monomeric feedstock in amounts of up to 5 parts of the adhesive properties

20th not noticeably changed.

It was also found that by the content of MMA at a constant catalyst concentration and presumably the adhesive strength also has a constant molecular weight of the polymer is improved.

It follows from the values that the omission of DAXAD-11 from the polymerization mixture (Example 20) does not affect the physical properties of the

Has 3Q polymer structure. The rise in WVTR values this Example in comparison with Example 17 probably depends more on the increased porosity than on the absence from DAXAD-11. When expected to have an effect on WVTR could be, one would have to assume that this would increase with the presence of DAXAD 11, due to

its complete water solubility.

All of the polymers shown in Table 7 showed excellent Initial adhesion to the skin including the so-called quick adhesion.

The production of non-self-adhesive glue flats results from the following examples, in which a monomeric composition of 68 parts of ethylene acrylate, 28 Parts of methyl methacrylate and 4 parts of acrylic acid are used became. The same catalyst and polymerization method as in Example 11 were used. In In each case, it was found that the latex obtained can be used as a binder adhesive in the manufacture of insulating strips of gypsum conduit pipe suitable is. The results are shown in the following table 9. "~

Table 9 Binder / adhesive latices

Example EMES DAXAD 11% Flok- PH- % Solid-% Um- Brookfield

No. Example No. Proportion pHm '''kungValuables' conversion Viscosity

40 9 5 0.5 O 6.2 49.8 97.1 105

10 5 0.5 O 6.5 49.7 96.9 -

2-5 0.5 2.6 6.1 49.5 99.1 - -

5 5 0.5 O 6.1 50.0 97.5

44 ^a 5 5 0.5 O 6.1 50.2 97.8 560

45 ^a 2 2.5 - 0 6.7 51.4 100 5o

46 ^a ^ 2 2.5 - 2.0 6.5 49.8 99.1 46

5 2.5 - O 6.9 50.5 98.4 116

5 2.5 - O 6.2 49.1 95.7 56

Parts per 100 parts of monomers 38-C reactor section

The Brookfield viscosity was measured using a # 2 spindle certainly.

BAD GRIGlNAt

COPY

In comparison with the above-mentioned pressure-sensitive adhesive, the latex viscosities of the products according to Examples 41 to 49 are in ' of the order of 50 compared to 1000 lower. It was in Examples 40, 41, 43, 44, 47 and 49 a excellent pure polymerization obtained. The LaI ices according to Examples 43, 46 and 47 showed flocculation of 0 to 3% and can be considered to be at the limit in terms of stability be judged lying down.

The latices according to Examples 40 to 49 were examined in two respects, namely for use as binders for a cloth impregnated with plaster in tape form and as a structural adhesive for the Finsat / an 'metallic Lines or pipes.

With regard to the plaster of paris tape adhesive, each of the fLatices examined was found to be non-tacky and, depending on the type of EMES used, resulted in the desired structural adhesion of the tape to the galvanized metal sheet. The latices of Examples 40 ^and 41, which were stabilized with the products according to Examples 9 and 10, apparently did not give the desired adhesion. Polymers which were stabilized with the products according to Examples 2 and 5 showed the desired adhesion. In order to obtain reproducible adhesion, it was found necessary to thicken the latex with Acrysol ASE95 or other known thickeners to a viscosity of about 1500 cP. The thickening of the latex changes the rheological properties of the latex sufficiently to prevent the latex from being absorbed by plaster of paris

30 which consequently remains at the interface.

From Examples 40 and 41 it can be seen that the distribution and maybe the concentration of ethoxy functionality along the EMES chain. The bigger the shorter the chain length of the polyethoxyeinhritol

BATH ORIGINAL

is apparently the molar amount of EMES in the polymer structure, assuming the same concentration in the polymer ionsreat ion. In addition, the hydrophilic character of the EMES compound increases with the length of the ethoxy chain.

The latices according to Examples 42 to 48 made plaster of paris tape waterproof and stabilized the plaster moldings or plaster splints that can be used in the medical field when immersed in water. The latices according to Examples 44, 45 and 47 had excellent slurry and coating stability, without further additives having to be added; these latices facilitated the intermediate adhesion of the plaster particles as well as their adhesion to cotton substrates, so that these latices were flexible, impregnated with plaster of paris Have ribbons or bandages made. A typical one Composition for this purpose is given below specified:

Wt% 20

Gypsum (ground) water EMES-Structure-Lateχ

² ^ A further investigation of these mixtures also showed that they can be used as binders for non-woven products.

Example 49
30th

Examples 1 to 10 were repeated using itaconic acid (49a to 49j).

Example 50

Examples 1 to 10 were each carried out using Citraconic acid (50a to 50j) repeated.

sy / do

26th , 3 65 , 7 8th , 0

Claims (16)

UEXKÜLL & STOLBERG PATENT LAWYERS EUROPEAN PATENT ATTORNEYS THE KENDALL COMPANY
One Federal Street Boston, Massachusetts 01201 V.St.A. DR J D FRHR by UEXKULL DR ULRICH GRAF STOL8ERG DIPL -ING JÜRGEN SUCHANTKE DlPL ING ARNULF HUBER DR ALLARD by KAMEKE DR KARL-HEINZ SCHULMEYER Prio: November 2, 1981 US 317 207 (19 138 sy / do) October 1982 Stabilizers for emulsion polymerization Claims Stabilizer for emulsion polymerization, marked by monomeric, polymerizable half-esters of αί-ethylenically unsaturated dicarboxylic acids and nonionic ethoxylates of the general formula - COOR R ₂ -C - COOR ₄ in the
R _{1 is} a CH-, Group represents, being in the first and second by an olefinic - to C ₄ alkyl) -C- or CH ₂ = C- If the group R. with C unsaturated bond is linked, while in the latter case C is a > CH group is Rp is a hydrogen atom or a C to C alkyl group and R ₃ and R each represent a hydrogen atom or a salt-forming group or an R -Z- (CH CH.O) group, with the proviso that one of the two radicals R 1 or R is a hydrogen atom or a salt-forming group and the other Radical represents a R -Z- (CH CH O) group, O L ·. L - ir *. where R ₁ - represents a hydrophobic radical, namely an alkyl group with 8 to 30 carbon atoms, a phenyl group or an alkylphenyl group with one to three C- to C .Q-alkyl groups, which is connected via a link Z, which is an oxygen, Is sulfur or nitrogen atom, is linked to the ethoxy chain, and wherein χ is an integer from 4 to 10. 2. Stabilizer according to claim 1, characterized in that the hydrophobic radical R, - a p-octyl or p-nonylphenyl group is. 3. Stabilizer according to claim 1, characterized in that that the hydrophobic radical R ^ is a straight-chain alkyl group with 11 to 15 carbon atoms and χ = 5. 4. Process for carrying out the emulsion polymerization of one or more monomeric acrylates on their own or in a mixture with one or more copolymerizable polar monomers of the vinyl or acrylic type, characterized in that the monomers with the stabilizer according to claims 1 to 3 and an effective Amount of a suitable polymerization catalyst at a temperature of about 5 to 80 C in one aqueous medium with a pH above about 4 in Brought into contact, a stable latex product with 45 to 55 wt.% solids that the weight ratio of monomers to stabilizer about 50: 1 to 10: 1 and that the monomers, the stabilizer and the catalyst are in the form of one aqueous pre-emulsion are added to the aqueous medium, wherein a first portion, which is about 20 wt.% of the total amount of pre-emulsion, initially is added and the remaining portion is added when the polymerization reaction has reached an exothermic initial stage, the pH value during the polymerization is maintained. 5. ' Method according to claim 4, characterized in that that it is carried out at a pH in the range 4-8. 6. The method according to claim 4, characterized in that that used as a catalyst tert-butyl hydroperoxide will. 7. The method according to claim 6, characterized in that ' that a small, effective amount of sulfoxylate / ferrous - ■ Ammonium sulfate is used. 8. The method according to claim 4, characterized in that that potassium persulfate is used as a catalyst. 9. The method according to claim 8, characterized in that that a small, effective amount of sodium bisulfate is used. NAGHSUiREiCHT i -A- 10. The method according to claim 4, characterized in that that 0.3 to 1.0 parts per 100 parts of the monomer of a sulfonated formaldehyde-naphthalene reaction product can be used. 11. The method according to claim 4, characterized in that that a monomeric acrylate with at least about 6b wt.% 2-Γ thy 1 hc-xy] acry] at is used. 12th Process according to Claim 11, characterized in that up to about 20% by weight of butyl acrylate and up to about 5% by weight of acrylic acid are also used. 13. The method according to claim 12, characterized in that cir.ß up to about 5 wt.% methyl methacrylate wetted will. 14. The method according to claim 13, characterized in that up to about 10 wt.% Vinyl acetate, 3 wt.% Acrylonitrile, 15 wt.% Acrylic E at thy1, 5 wt.% Dimethy1 aery1-amide and / or 20 wt.% of the reaction product of hydroxypropyl acrylate and succinic anhydride are used. 15. The method according to claim 4, characterized in that that a monomeric acrylate with at least about 65 wt.% Fi thy] ac ry 1 at is used. © AD ORIGINAL . b 16. Use of a latex produced by the method according to claim 4 to 15 as an adhesive, pressure-sensitive adhesive or as an adhesive in an aqueous plaster slurry .