WO2000056805A1

WO2000056805A1 - Polyurethane foam stabilizers

Info

Publication number: WO2000056805A1
Application number: PCT/US2000/008002
Authority: WO
Inventors: Wojciech Grabowski; Louis Muller
Original assignee: CK Witco Corp
Current assignee: Lanxess Solutions US Inc
Priority date: 1999-03-24
Filing date: 2000-03-24
Publication date: 2000-09-28
Anticipated expiration: 2001-09-24
Also published as: AU4177200A; CA2342931A1

Abstract

Polyurethane foam formulations contain stabilizing silicone surfactant compositions which include a first silicone characterized by having from about 2 to about 205 siloxane repeat units and which includes at least one substituent which is a polyhydric organicgroup (R2), an ester, ether, acetal or ketal derivative of a polyhydric organic group (R3) or a phenolic group (R4). The first silicone structures can be easily tailored for different types of foam formulations. The surfactant may optionally also include a second silicone selected from the group consisting of a silicone oil and a polyether silicone copolymer, in an amount which does not exceed 50 % of the total weight silicone surfactant in the surfactant composition.

Description

POLYURETHANE FOAM STABILIZERS

BACKGROUND OF THE INVENTION

Silicone surfactants useful for controlling stabilizing polyurethane foams are known. Specific patent documents relating to such silicones and to their use include US 5,789,454; US 5,525,640; US 5,432,206; US 5,192,812; US 5,145,879; US 5,070,112; US 5,045,571 ; US 5,041,468; US 5,001,248; and US 4,746,683, the entire disclosures of which are incorporated herein by reference. Typically silicones used as polyurethane foam stabilizers are copolymers containing polyoxyalkylene moieties thereon. Much of the research on such silicone surfactants has focused on the structure, size and distribution of alkylene oxide moieties. This approach, however, has not proved entirely satisfactory. A need therefore exists for an alternative approach to preparing silicone surfactants useful in stabilizing polyurethane foams.

In US 5,070,112 there are described surfactant blend compositions comprising a mixture of between 5 and 20% by weight of a silicone having phenolic group substitution and between 95 and 80 % by weight of a silicone/ ethylene oxide/propylene oxide copolymer.

Silicone polymers having polyhydric groups thereon and useful as defoamers for diesel fuel and other hydrocarbon liquids are described in DE 4032006 (unsaturated polyhydric groups) and in WO 97/38067 (saturated polyhydric groups), both incorporated herein by reference in their entirety.

SUMMARY OF THE INVENTION

The invention hereof, in various aspects, provides novel polyurethane foam compositions employing silicone surfactants; new silicone surfactants useful in the stabilization of polyurethane foams; and a novel process for modifying the properties of polyurethane foam stabilizing silicone surfactants.

In one aspect the invention is a formulation curable to a foam comprising: an active hydrogen component having an average of two or more active hydrogen groups per molecule; a polyisocyanate component having an average of two or more isocyanate groups per molecule; a blowing agent; and a silicone surfactant composition comprising a first silicone having from about 2 to about 205 siloxane repeat units and which includes at least one substituent which is a polyhydric organic group (R²), an ester, ether, acetal or ketal derivative of a polyhydric organic group (R³) or a phenolic group (R⁴), and wherein the surfactant composition comprises no more than 50% by weight of a polyether silicone copolymer. Preferred such first silicones may be represented by the formula:

M*_tD_xD*_yM_u (I) wherein M* is R^RSIO_{Q 5}-; D is -R^SiO-; D* is -R'RSiO-; M is R^SIO_{Q 5}-; R¹ is an aromatic or saturated aliphatic hydrocarbon group; R is R², R³, R⁴ or R⁵; R², R³ and R⁴ are as previously defined; R⁵ is a polyether group; there is at least one group R², R³ or R⁴ group on the molecule, no more than 90% of the R groups are R⁵ groups; t and u are 0-2; t+u = 2; x+y=l-200; and t+y is at least 1.

Silicone surfactants, as described above, in which the first silicone has a combination of substituent groups which include at least one each substituent selected from R², R³ and R⁴, and also has at least two different substituents selected from R², R³, R⁴ and R⁵ constitutes a further aspect of the invention. Particular such combinations include R² and R³; R² and R⁴; R² and R⁵; R³ and R⁴; R³ and R⁵; and R⁴ and R⁵. Such silicones may be produced by a hydrosilation reaction process which constitutes yet a further aspect of the invention. In the inventive process, suitable aliphatically unsaturated compounds are sequentially or concurrently reacted with a hydrido silicone. The surfactant composition may have the first silicone, as defined above, as the sole component thereof. Alternatively, the first silicone may be used in combination with a silicone polyether copolymer or a silicone oil, provided, however, that the first silicone, or a mixture of first silicones, represents about 50% or more of the total silicone surfactant weight. A further aspect of the invention is a silicone surfactant composition comprising a mixture of at least one said first silicone and at least one second silicone selected from the group consisting of of a silicone polyether copolymer or a silicone oil, the first silicone constituting about 50% or more of the total weight of silicone surfactant.

DETAILED DESCRIPTION OF THE INVENTION The silicone surfactants used in the invention are preferably linear, although an occurrence of one or two branching moieties in a surfactant molecule should be considered to also be encompassed within formula (I), above. The surfactants may be produced from hydrido functional silicones using appropriate hydrosilation reactions to introduce the R groups into the molecule and, if desired, to introduce variation in the R¹ groups. The hydrido functional silicones suitably may be represented by the formula:

M'_tD_xD'_yM_u (II) wherein M' is R^HSIO_{Q 5}-; D is -R^SiO-; D' is -R^RSiO-; and M is R^SIO_{Q 5}-., and R¹, t, x, y and u are as previously defined.

In the formulae (I) and (II) above, R¹ is an aromatic or saturated aliphatic hydrocarbon group. Specific examples include methyl, ethyl, propyl, octyl, decyl, dodecyl, stearyl, phenyl, methylphenyl, dimethylphenyl, phenylethyl, cyclohexyl, methylcyclohexyl, and the like. Preferred R¹ groups are alkyl, most suitably methyl, optionally with relatively minor amounts of C₆-C₂₂ alkyl groups. The longer alkyl groups may be introduced by hydrosilation of a corresponding C₆-C₂₂ olefin. For instance a polydimethylsiloxane having a specific content of methylhydrogendisiloxy and/or dimethylhydrogensiloxy units thereon can be used to hydrosilate a higher terminal olefin such as decene to produce a desired content of decyl groups grafted onto the polymer molecule. In preparing the silicone copolymers used in the invention, such hydrosilations may be desirable to consume any excess silicon hydride functionality in the starting hydrido silicone polymer over that needed to introduce the respective R², R³, R⁴ and/or R⁵ groups onto the molecule. Long chain alkyl groups can also be introduced to modify solubility or the hydrophilic/hydrophobic balance properties.

As used herein, the term "polyhydric organic group" refers to an organic group having two or more hydroxyl groups thereon. The polyhydric organic groups R² may be aliphatic, low molecular weight hydrocarbon groups, optionally interrupted with an ether oxygen atom and/or a tertiary amino group, and having at least two hydroxy groups thereon. Polyhydric groups interrupted with tertiary amino groups may be prepared as described in copending US provisional application 60/102,039 filed Sept. 28, 1998, incorporated herein by reference in its entirety. Preferred organic groups are saturated ether or saturated hydrocarbon groups. Polyhydric unsaturated aliphatic groups may be employed but are generally less preferred. The R² group preferably has a molecular weight between about 134 and about 644, and more preferably between about 134 and about 400. The R² group preferably is saturated completely, as disclosed in WO 97/38067, although unsaturated polyhydric groups such as disclosed in DE 4032006 may also be used. The R² group may be provided on the molecule by a hydrosilation grafting reaction wherein a silicone polymer having a content of silicon hydride groups, typically present as methylhydrogendisiloxy and/or dimethylhydrogensiloxy repeat units, can be used to hydrosilate an unsaturated hydrocarbon group on a polyhydric compound having an unsaturated site such as an allyl, methallyl or vinyl group.

Examples of compounds which may be hydrosilated in this manner to form R² groups include trimethylolpropane monoallyl ether (TMPMAE), alkoxylated trimethylolpropane monoallyl ether, pentaerythritol allyl ether, alkoxylated pentaerythritol allyl ether, tri-isopropanolamine allyl ether, alkoxylated allyl sorbitol, 1,3- allyloxypropanediol and 2-butyne-l,4-diol. Alkoxylation may be ethoxylate, propoxylate, butoxylate or mixtures thereof and may contain multiple alkoxylate units per molecule, preferably from 1-6 such repeat units. Polyhydric compounds having acetylenic unsaturation, such as 2-butyne-l,4-diol, may be employed to provide polyhydric organic groups. The polyhydric group is preferably saturated and therefore an olefinically unsaturated polyhydric compound is preferably be used to prepare the R² groups. TMPMAE is preferred. An aliphatically unsaturated diol or polyol can be reacted to form esters, ethers, acetals or ketals, in accordance with well known reactions, and then the resulting unsaturated compound hydrosilated in like manner to form groups R³. if desired. For instance an unsaturated diol can be transformed into a corresponding cyclic formal via reaction with formaldehyde, and the resulting cyclic olefins can be grafted onto the siloxane backbone by hydrosilation.^" Conversely, the cyclic formal of trimethylolpropane may be prepared and the resulting mono-ol converted to the alkali alkoxylate and reacted with an unsaturated halide such as allyl chloride or methallyl chloride. This latter procedure, with an intermediate alkoxylation of the cyclic formal of trimethylolpropane before conversion of alcohol to alkali alkoxylate, can conveniently be used to prepare cyclic trimethylolpropane formal alkoxylate ethers. Alternatively, a polyorganosiloxane having polyhydric groups R² may have a selected fraction of the polyhydric groups converted into ester, ether, acetal or ketal derivatives, using mild condition reactants so as to avoid destroying the siloxane backbone, in order to fine tune the solubility parameters of the surfactant. The fraction of R² groups so converted may be up to 100%, preferably not more than 50%, more preferably not more than 10%. The R⁴ groups are suitably derived from phenol compounds having unsaturated olefinic or acetylenic group thereon. A similar hydrosilation reaction to those described above may be used. A typical example of a phenol compound which may be grafted to a silicone polymer in this manner is eugenol (i. e. 4-allyl-2- methoxyphenol). Other phenol compounds which may be employed include vinylphenol, vinyl guaiacol and 4-allylphenol. The phenolic R⁴ groups may be the sole R groups on the molecule but are preferably employed, if at all, in mixture with polyhydric R² groups in an amount, relative to the R² groups, of no more than 1:1, desirably no more than about 0.4: 1.

The R⁵ groups are polyether groups. They may be provided on a silicone backbone by a hydrosilation grafting reaction using a silicon hydride functional silicone and a polyether having an olefinically unsaturated end group, such as an allyl group. The polyether groups may be any polyether known as usefully employed on silicone surfactants for polyurethane foam stabilization, especially those based on ethylene oxide, propylene oxide, butylene oxide or tetrahydrofuran. Preferred polyether groups are derived from allyl started polyethylene oxides or polyethylene oxide/polypropylene oxide polyethers having a molecular weight of about 100 to about 350. Also preferably the ethylene oxide content of the polyether is at least 75% by weight, most preferably 100%) . The polyether group may suitably be terminated with a hydroxy, alkoxy or acetoxy group.

Silicone surfactants having two or more of R², R³, R⁴ and/or R⁵ groups, may be prepared by hydrosilation of a mixture of two or more members of the group consisting of unsaturated polyhydric compounds, derivatives thereof, unsaturated polyether compounds and unsaturated phenol compounds. A sequential hydrosilation process in which the different unsaturated compounds are sequentially added to silicone having an excess of SiH groups, relative to each of the unsaturated compounds individually, may also be employed.

The polyhydric groups R² typically provide greater hydrophilic character than an EO moiety so that larger starting hydrido silicones can be used in synthesizing the silicone surfactants of the invention. That is, compared to conventional silicone polyether copolymer surfactants, the invention permits a surfactant having a higher molar fraction of silicone relative to organic may be used while still maintaining adequate control over the polarity of the polymer. Furthermore, an R³ group in which all of the hydroxyl groups are derivatized typically provides a greater hydrophobic character than a PO unit. Consequently, a wide range of properties can be obtained merely varying the R² to R³ ratio. Since an R³ group can be prepared by derivatization of the R² group, a single hydrosilation product can be used to provide an assortment of surfactants having a range of properties. Still further, another assortment of surfactants can be easily prepared by varying the ratio of components in the hydrosilation reaction using a single set of reactant compounds. Thus, many surfactants can be prepared from a single hydrido silicone, a single set of R group forming compounds (e.g. a single aliphatically unsaturated polyhydric compound, a single unsaturated derivative of a polyhydric compound, a single aliphatically unsaturated polyether, and/or a single aliphatically unsaturated phenolic compound), merely by varying the relative ratio of the R group forming compounds in the reaction. These strategies provide a much more convenient system for modifying surfactant properties than the conventional tactic of changing polyether reactants, (which requires an inventory of polyethers with many different EO/PO ratios and/or molecular weight profiles). During manufacture, it is often advantageous to add a solvent to ensure that the reactants are well mixed throughout the reaction. Solvents used for these purposes include DPG (dipropylene glycol), toluene and any other solvent of which has suitable solubility characteristics, such as isopropanol, various aromatic solvents such as SOLWESSO 150, aliphatic ester alcohols such as TEXANOL (2 ,2,4-trimethyl-l,3- pentanediol monoisobutyrate), isophorone, mixtures of same, and the like. Moreover, reactive natural diluents, such as castor oil, and non-reactive diluents, such as soybean oil, may be used. For the sake of safe transportation, volatile solvents such as toluene and isopropanol can optionally be removed. Non-volatile solvents or those of a high flash point (e.g., DPG) do not pose the same safety problems, and there is no need to remove them.

Foam formulations

In producing the polyurethane foams using the surfactants described above, an organic compound having two or more active hydrogen groups per molecule is reacted with a polyisocyanate. The organic compound having two or more active hydrogen groups per molecule is preferably a polyamine or a polyol, most preferably a polyol. Suitable polyols have an average of at least 2 and typically 2.1 to 3.5 hydroxyl groups per molecule and include compounds which consist of carbon, hydrogen and oxygen, and compounds which may also contain phosphorus, halogen, and/or nitrogen. Typical polyols are polyester polyols, polymer polyol graft compounds and polyether polyols. Choice of polyol tipping, i.e. primary or secondary hydroxy termination, and/or polyol molecular weight are factors which may be varied by the formulator according to the properties desired in the formulation, in curing and/or in the cured foam. Polyether polyols are generally preferred. Typically the polyether polyol is prepared by reacting a low molecular weight polyfunctional alcohol, e.g. ethylene glycol, propylene glycol, 1-4- butane diol, glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol sorbitol, sucrose or the like with one or more lower alkylene oxides. Such polyols are well known in the art and are commercially available. The organic isocyanates that are useful in producing polyurethane foams in accordance with this invention are also well known in the art and are organic compounds that contain at least two isocyanate groups per molecule. Any such compounds or mixtures thereof can be employed. Isocyanates may be aromatic or aliphatic and may be monomeric or oligomeric compounds. Examples of suitable diisocyanates include toluene diisocyanate, diphenylmethane diisocyanate, 1,6- hexamethylene diisocyanate, isophorone diisocyanate, methylene-bis-(4-cyclohexane isocyanate) and oligomers thereof.

The urethane foaming reaction is usually effected in the presence of a minor amount of a base catalyst, preferably an amine catalyst and usually a tertiary amine. Known metal catalysts may be used instead of, or in addition to, the amine catalyst in the urethane foam reaction mixture. Useful metal catalysts include organic derivatives of tin, e.g. tin (II) alkoxides, tin (II) carboxylates, dialkyl tin salts of carboxylic acids or hydrohalic acids.

In order to produce a foam a blowing agent is provided during the polyurethane forming reaction. The blowing agent may be water, which reacts with isocyanate to generate carbon dioxide in situ, or a fluorocarbon such as dichlorodifluoromethane, 1,1-dichloro-l-fluoroethane, l-chloro-l,l-difluoroethane, 2,2- dichloroethane or the like. Non-fluorinated organic compound blowing agents such as pentane and acetone may also be employed as blowing agents. The amount of blowing agent required will vary according to the density of the foam which is desired. Suitable levels of blowing agent are known to the skilled person.

Another technology for blowing polyurethane foams uses supplemental added inert gases as part of the blowing agent for flexible polyurethane foams, as described in EP 0 645 226 A2, incorporated herein by reference. In such a system auxiliary gas is added to the system as a blowing agent and is used in conjunction with the CO₂ generated from the reaction of isocyanate with water. The inert gas is dissolved in the foam formulation at elevated pressures, but flashes out of solution at atmospheric pressure, thereby blowing the foam. An exemplary such gas is CO but nitrogen, air or other common gases, including hydrocarbon gases, such as methane and ethane may also be used. Other additives may be added to the polyurethane foam to impart specific properties to the foam, including, but not limited to, coloring agents, flame retardants, UV stabilizers, antioxidants and GEOLITE^® Modifier foam additives (available from Witco Corp., Greenwich, Conn.).

It is understood that the relative amounts of the various components of the foam formulation are not narrowly critical. The polyether polyol and polyisocyanate are present in the foam-producing formulation in a major amount. The relative amounts of these two components in the amount required to produce the desired urethane structure of the foam and such relative amounts are well known in the art. The blowing agent, catalyst and surfactant are each present in a minor amount sufficient to foam the reaction mixture, the catalyst is present in a catalytic amount i.e., that amount necessary to catalyze the reaction to produce the urethane at a reasonable rate, and the surfactant is present in an amount sufficient to impart the properties desired.

The surfactants are typically present at 0.01 to 5 Wt. percent of the total reaction mixture, preferably 0.2 to 1.5 wt. percent. It is sometimes convenient to add the surfactant to the reaction mixture in a premix with one or more of the blowing agents, polyol and/or catalyst components.

The polyurethane foams produced in accordance with the present invention may be rigid, flexible, microcelluar, mechanically froathed, molded, high resiliency, or slab stock. They can be used in the in the manufacture of textile interliners, cushions, mattresses, padding, carpet underlay, packaging, gaskets, sealers, thermal insulators and the like.

The invention is illustrated by the following non-limiting examples.

EXAMPLES Silicone surfactants were produced by hydrosilating one or more members of the group consisting of allyl started poly ethers of varying blend average molecular weights (BAMW); TMPMAE (trimethylolpropane monoallyl ether); and/or TMPMAE formal (formaldehyde condensate of trimethylolpropane monoallyl ether), in the relative ratios shown in Table 1 , using a hydrido siloxane of formula II where R is methyl and t, u, x and y are as given in Table 1. For the A-series examples, those with polyether BAMW of 3200 used a polyether with an EO/PO ratio of 40/60. For the remaining A- series examples the same EO/PO polyether was used, adjusted to the indicated BAMW by blending with a 400 mol. wt. 100%) EO polyether. The B-series examples all used a polyether having an EO/PO ratio of 75/25. Three different hydrido silicones (types 1, 2 and 3, respectively) were used. Surfactants for flexible foams are indicated by the letter A in the Example number and surfactants for rigid foams are indicated by the letter B in the Example number. Examples A-11, A-12 and A-27, which are made entirely from polyether are comparative examples.

' As the formal Two different foam formulations were used to assess the flexible foam silicone surfactants A. The formulations are shown in Table 2. The formulation FA1 results in extremely low foam density (8 kg/m³) and the foam rise, the top collapse of foam made (TCj and the foam structure are of great importance. The formulation FA2 the form rise, top collapse and the breathability (airflow) of the foam are major properties as the foam structures are usually similar unless a serious deficiency in foam rise is recorded. This type of foam is not currently made by foam producers, due to the use of CFC blowing agent, but experience shows this formulation as representative of the processing latitude of a stabilizer and is therefore still useful as a test formulation. Foam stabilizers yielding more open foams are usually considered to have a desirable wide processing latitude. Table 2 gives detailed formulations.

Products of Dow Corp Product of ICI

³ Products of Witco Corp

Foam evaluation results are collected in Table 3 where the concentration of the foam stabilizing surfactant is given on the basis of parts by weight per 100 parts of polyol (php). The airflow value indicates the amount of air passing through a foam specimen of a fixed thickness and under standardized pressure. For the sake of comparison two reference stabilizers are introduced: RA1 - currently used in the production of very low density foam and RA2. a state-of-the-art stabilizer commonly employed in Europe. RA2 produces very open foams.

Table 3

(*) foam rise relative to RA-1 used at 1.50 php

Examples Al 1 to A18 are made with the same siloxane backbone, with RA-1, A-11, A-12, A-27 and RA-2 being Comparative Examples. It can be seen from Table 3 that the introduction of TMPMAE effects an increase in the foam rise and reduces the top collapse of foams made in FA1. This is particularly visible in the Example A15 which comes with a substantially improved foam rise at 1.5 parts.

The stabilizing surfactants A-16, A-27, A-28 and RA-1 were also tested using a small batch foam machine with formulation FA-1 to make foam blocks having a height exceeding one meter. Such foaming conditions are more critical than the bench test reported in Table 3. The foam made with the Example A-27 comes with an unacceptable foam structure that is coarse with some internal voids. Examples A- 16 and A-28 yielded foams at least matching the reference RA-1 in terms of foam structure and offer improved foam rise. The copolymers made with a formal derivative of TMPMAE offer less improvement in the formulation FA1. However, in the FA2 formulation their use allowed production of foams which were very stable and very open as well (A- 14, A 17). Structures made with a polyether and TMPMAE yield very stable foams in FA2 but the airflow recorded is somewhat low. However, higher airflow than that for reference RA-1 can be obtained as illustrated with example A-18.

Silicone structures identified by the letter designation "B" in Table 1 were used to make rigid polyurethane foam blown with hydrocarbons. Foams of good structure and low foam thermal conductivity were made in the laboratory set-up.

Molded High Resiliency Foams Examples

Silicone surfactants were produced by hydrosilating one or more members of the group consisting of: TMPMAE;

TMPMAE formal ("TMPMAE.F" in Table 4); Eugenol; and the allyl ethers of ethoxylated cyclic trimethylolpropane formal ( the (average) mono, di, tri and tetra ethoxylates are designated respectively, "CTF1," "CTF2," "CTF3" and '"CTF4" in Table 4), in the relative ratios shown in Table 1 , using a hydrido siloxane of formula II above, where R is methyl and t, u, x and y are as given in Table 4.

Table 4

The three formulations given below in Table 5 may be used for the manufacture of foam cushions such as in the fabrication of automotive seats or in household furniture. Formulation B reflects an average formulation used in the industry.

Table 5

¹ Glycerol started polyol, molecular wt 6000, high reactivity through EO tip.

² Base polyol grafted with a polymerizing dispersion of styrene and acrylonitrile to a poly(styrene-sacylonitrile) content of 40% by weight of the graft polyol.

Diethanol amine.

Foam formulations were prepared using the surfactants described in Table 4 using the average formulation B of Table 5, except where the surfactant designation in Table 6 is followed by the letter A, in which case formulation A of Table 5 was used. The amount of diethanol amine was 1.0 phr, except as indicated in the following discussion of specific foam tests. Silicones described in Table 4 were added to the formulations as solutions in inert solvent. The total weight basis concentration of the respective silicones is indicated in Table 6 as % active. In some cases influence of a silicone oil co-surfactant was added and the weitht basis concentration of the latter is also indicated in Table 6. Three commercial silicone surfactants, "Ref A," "Ref B" and "Ref C", respectively, were also used as comparative Examples.

Three tests were made on the foams produced to compare the performance of the surfactant in terms of foam openness imparted foam stability and resulting cell structures. The definitions of the measured parameters are as follows:

-Foam Openness is measured as "Force-To-Crush": ("FTC"): the FTC is the peak force in N required to deflect a foam pad with the standard ³²³ cm² (50 in²) indentor, one minute after demold, to 50% of its original thickness. The FTC value is a good relative measure of the degree of foam openness: the lower the value, the more open the foam is. To make the test more selective the level of DEO A used here was 1.2 php. This resulted in a tighter foam and hence a higher "FTC"

-Foam Stability ("STAB") is tested by molding a cushion with a mold equipped with several (typically 4) venting holes that are big (4 mm in diameter). The foam molded under this condition usually suffers severe instability which results in collapsed holes just under the venting holes. The top part of the foam pad is cut to show the extend of collapse. The stability is here rated from 1 to 10 where 1 denotes no vent collapse and 10 total collapse. For this test the DEOA level was reduced to 1.0 php as this leads to less stable foam and hence the test is more severe for the surfactant.

- Cell Structure ("STR") is observed on the cushion molded to measure the FTC. The skin of the pad is cut with a thickness of about 1 cm. This allows the observation of the cell structure both by transparency to look to the skin structure and straight to view the cell structure of the bulk foam. The person skilled in the art is looking for a cell structure said to be slightly coarse and irregular without skin effect. Cell structures qualified with "*" are good, whereas a rating of "**" denotes acceptable cell structure with a tendency towards big cells under the skin and "***" degraded cell structure and "****" unacceptable coarse and regular cell structure in the bulk of the foam.

The corresponding results are discussed in the following Table 6.

Table 6

The ideal silicone surfactant for this application gives very open foams with a FTC ranging from 100 N to less than 500 N along with an acceptable cell structure rated as "*" or "**" still producing a good stability rated below 5. The difficulty is to produce open foam while preserving stability as it can be observed with the results obtained with the 3 commercial references, Ref A, RefB and Ref C. when stability is improved to a rating of 3 the FTC reaches a relatively high value denoting tight foam. From the above table it can be seen that several structures based on the novel pending groups offer the benefit of substantially open foam along with superior stability.

The foregoing Examples demonstrate that polyhydric groups R², as well as their derivatives R³ and phenolic groups R⁴, optionally in combination with polyether groups, function as suitable organic groups to be used in the preparation and fine tuning- up of molecular properties of silicone polymers used for polyurethane foam stabilization.

The adjustment of molecular properties can be accomplished by modification of the siloxane segmenf lengfh, the degree of its substitution and the nature of the grafted groups. The use of compact, highly polar moieties such as polyhydric derivatives allows a desired polarity of organosilicone to be maintained together with a high molar contribution of siloxane unites in the copolymer. The combination of the latter with an adequate overall polarity permits easy adjustment to improve the performance characteristics of urethane foam stabilizers in specific applications. The above Examples and disclosure are intended to be illustrative and not exhaustive. These examples and description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the attached claims. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims attached hereto.

Claims

CLAIMSWhat is claimed is:

1. A formulation comprising: an active hydrogen component having an average of two or more active hydrogen groups per molecule; a polyisocyanate component having an average of two or more isocyanate groups per molecule; a blowing agent; and a silicone surfactant composition comprising a first silicone having from about 2 to about 205 siloxane repeat units and which includes at least one substituent which is a polyhydric organic group (R²), an ester, ether, acetal or ketal derivative of a polyhydric organic group (R³) or a phenolic group (R⁴), and wherein the surfactant composition comprises no more than 50% by weight of a polyether silicone copolymer.

2. A formulation as in claim 1 wherein said first silicone has the formula:

M*_tD_xD*_yM_u (I) wherein M* is R^RSiOo ₅-; D is -R^SiO-; D* is - ^RSiO-; M is R^SiOø ₅-; R¹ is an aromatic or saturated aliphatic hydrocarbon group; R is R², R³, R⁴ or R⁵; R², R³ and R⁴ are as defined in claim 1 ; R⁵ is a polyether group; there is at least one group R², R³ or R⁴ group on the molecule, no more than 90% of the R groups are R⁵ groups; t and u are 0-2; t+u = 2; x+y= 1-200; and t+y is at least 1.

3. A formulation as in claim 2 wherein R¹ is alkyl.

4. A formulation as in claim 2 wherein R⁵ is a group produced by hydrosilation of a polyether compound having an olefinic or acetylenic terminal group.

5. A formulation as in claim 2 wherein R¹ is methyl, R² is an organo group produced by hydrosilation of trimethylolpropane monoallyl ether, R³ is the formal of trimethylolpropane monoallyl ether, R⁴ is a group produced by hydrosilation of eugenol, and R⁵ is a group produced by hydrosilation of an allyl started polyether compound comprising at least weight percent efhylene oxide units and having a molecular weight of from about 100 to about 3,500.

6. A formulation as in claim 1 wherein said first silicone comprises at least one R² group and wherein R² is an organo group produced by hydrosilation of a polyhydric compound selected from the group consisting of trimethylolpropane monoallyl ether, alkoxylated trimethylolpropane monoallyl ether, pentaerythritol allyl ether, alkoxylated pentaerythritol allyl ether, tri-isopropanolamine allyl ether, alkoxylated allyl sorbitol, 1,3-allyloxypropanediol and 2-butyne-l,4-diol.

7. A formulation as in claim 1 wherein said first silicone comprises at least one R² group and wherein R² is an aliphatic hydrocarbon group optionally interrupted with an ether oxygen atom and/or a tertiary amino group and having at least two hydroxy groups thereon.

8. A formulation as in claim 1 wherein said first silicone comprises at least one R³ group and wherein R³ is the cyclic formal of trimethylolpropane monoallyl ether or of alkoxylated trimethylolpropane monoallyl ether.

9. A formulation as in claim 1 wherein said first silicone comprises at least one R⁴ group and wherein R⁴ is a group produced by hydrosilation of a phenol compound selected from the group consisting of eugenol, vinyl phenol, vinyl guiacol and allyl phenol.

10. A formulation as in claim 1 wherein said silicone surfactant composition further comprises a said polyether silicone copolymer or a silicone oil.

1 1. A process for manufacturing a polyurethane foam comprising mixing: an active hydrogen component having an average of two or more active hydrogen groups per molecule; a polyisocyanate component having an average of two or more isocyanate groups per molecule; a blowing agent; and a surfactant composition, wherein the surfactant composition comprises: a first silicone having from about 2 to about 205 siloxane repeat units and which includes at least one substituent which is a polyhydric organic group (R²), an ester, ether, acetal or ketal derivative of a polyhydric organic group (R³) or a phenolic group (R⁴), and wherein the surfactant composition comprises no more than 50% by weight of a polyether silicone copolymer.

12. A process as in claim 11 wherein the first silicone has the formula:

M*_tD_xD*_yM_u (I) wherein M* is R^RSIO_{Q 5}-; D is -R^SiO-; D* is -R^!RSiO-; M is R^SIO_{Q 5}-; R¹ is an aromatic or saturated aliphatic hydrocarbon group; R is R², R³, R⁴ or R⁵; R², R³ and R⁴ are as defined in claim 1 ; R⁵ is a polyether group; there is at least one group R², R³ or R⁴ group on the molecule, no more than 90%> of the R groups are R⁵ groups; t and u are 0-2; t+u = 2; x+y= 1-200; and t+y is at least 1.

13. A silicone having from about 2 to about 205 siloxane repeat units, the silicone including at least one substituent which is a polyhydric organic group (R²), an ester, ether, acetal or ketal derivative of a polyhydric organic group (R³) or a phenolic group (R⁴), and having at least two different substituents which are members of the group consisting of R², R³, R⁴ and R⁵, wherein R⁵ is a polyether group, and wherein no more than 90% of the total of R², R³, R⁴ and R⁵ groups are R⁵ groups.

14. A silicone as in claim 13 having the formula:

M*_tD_χD*_yM_u (I) wherein M* is R'₂RSiO_{0 5}-; D is -R^SiO-; D* is -R'RSiO-; M is R'₃SiO_{0 5}-; R¹ is an aromatic or saturated aliphatic hydrocarbon group; R is R², R³, R⁴ or R⁵; t and u are 0-2; 5 t+u = 2; x+y=l -200; and t+y is at least 1.

15. A silicone as in claim 13 wherein said substituents include at least one each of R² and R³.

10 16. A silicone as in claim 13 wherein said substituents include at least one each of R² and R⁴.

17. A silicone as in claim 13 wherein said substituents include at least one each of R² and R⁵.

15

18. A silicone as in claim 13 wherein said substituents include at least one each of R³ and R⁴.

19. A silicone as in claim 13 wherein said substituents include at least one 20 each of R⁴ and R⁵.

20. A process for producing a silicone surfactant, comprising sequentially or concurrently hydrosilating a plurality of different aliphatically unsaturated compounds with a hydrido silicone having from about 2 to about 205 siloxane repeat units wherein:

25 the aliphatically unsaturated compounds comprise at least two members selected from the group consisting of polyhydric compounds having an aliphatically unsaturated group thereon; ester, ether acetal or ketal derivatives of a polyhydric compounds having an aliphatically unsaturated group thereon; phenols having an aliphatically unsaturated group thereon; and polyethers having

30 an aliphatically unsaturated group thereon, at least one of said unsaturated compounds is a member of the group consisting of polyhydric compounds having an aliphatically unsaturated group thereon; ester, ether acetal or ketal derivatives of a polyhydric compounds having an aliphatically unsaturated group thereon; and phenols having an aliphatically unsaturated group thereon, and no more than 90% of said unsaturated compounds are polyethers having an aliphatically unsaturated group thereon.

21. A process as in claim 20 wherein the hydrido silicone has the formula

M'_tD_xD'_yM_u (II) where M' is R^HS-O^-; D is -R^SiO-; D' is -R'HRSiO-; and M is R^SiOø ₅-; t and u are 0-2; t+u = 2; x+y= 1-200; and t+y is at least 1,

22. A process as in claim 20 wherein said unsaturated compounds include at least one polyhydric compound selected from the group consisting of trimethylolpropane monoallyl ether, alkoxylated trimethylolpropane monoallyl ether, pentaerythritol allyl ether, alkoxylated pentaerythritol allyl ether, tri-isopropanolamine allyl ether, alkoxylated allyl sorbitol, 1,3-allyloxypropanediol and 2-butyne-l,4-diol.

23. A silicone surfactant composition comprising a blend of at least one first silicone having from about 2 to about 205 siloxane repeat units and which includes at least one substituent which is a polyhydric organic group (R²), an ester, ether, acetal or ketal derivative of a polyhydric organic group (R³) or a phenolic group (R⁴), and at least one second silicone selected from the group consisting of a silicone oil and a polyether silicone copolymer, said first silicone constituting about 50% or more of the total weight silicone surfactant in said composition.

24. A silicone surfactant composition as in claim 23 wherein said first silicone has the formula:

M*_tD_xD*_yM_u (I) wherein M* is R^RSiOø ₅-; D is -R^SiO-; D* is -R^SiO-; M is R^SiO^-; R¹ is an aromatic or saturated aliphatic hydrocarbon group; R is R², R³, R⁴ or R⁵; R², R³ and R⁴ are as defined in claim 1 ; R⁵ is a polyether group; there is at least one group R², R³ or R⁴ group on the molecule, no more than 90% of the R groups are R⁵ groups; t and u are 0-2; t+u = 2; x+y=l -200; and t+y is at least 1.

25. A polyurethane foam produced by curing a formulation as in claim 1.

26. A polyurethane foam produced by the process of claim 11.