DE2728284C2 - Polymer/polyol preparations and their use for the production of polyurethane - Google Patents

Description

The present invention relates to novel polymer/polyol preparations and their use for producing optionally foamed polyurethanes.

Polymer/polyol dispersions have been and are currently used in the manufacture of polyurethane products. These dispersions result in polyurethane products with many different desirable properties.

There are numerous publications on the preparation of polymer/polyol dispersions, such as US-PS 33 04 273, 33 83 351 and Re 28 715 (reissue of 33 83 351), GB-PS 10 22 434, Canadian patents 7 35 010 and 7 85 835, US-PS 38 23 201, DE-OS 25 00 240 and US-PS 39 53 393 and 36 55 553.

The patents cited above after GB-PS 10 22 434 describe the preparation of polymer/polyol dispersions by polymerizing one or more ethylenically unsaturated monomers in situ in a polyol to form dispersions of small polymer particles dispersed in the polyol. These dispersions are then mixed with polyisocyanate and other polyurethane-forming reactants and reacted to form improved polyurethane products. These processes using polymer/polyol dispersions are widely practiced on an industrial scale.

Although the known polymer/polyol dispersions give useful results, there is a need in the polyurethane industry for improved polymer/polyol dispersions that can speed up production, handle larger volumes, etc. In particular, there is a need for more stable dispersions that can be stored until use without noticeable settling. In the past, little attention was paid to the settling properties (nucleation), viscosity or filterability of polymer/polyols in actual commercial use. These properties are now of paramount importance. Filterability, settling properties and viscosity are now important due to more complicated machine systems in large volume production. Furthermore, the known dispersions with the relatively low molecular weight polyols, such as dipropylene glycols, could not be produced in a highly stable state, making the lower molecular weight materials less desirable than higher molecular weight materials for the polyol component of the polymer/polyol dispersions. The lower molecular weight polyols are of value in cases where low viscosity is important, such as for foams, coatings and certain types of sealants.

The use of polyol blends to produce polymer/polyols has been demonstrated in many of the above Publications. The use of low molecular weight polyols in polymer/polyol dispersions was mentioned in GB-PS 10 22 434 and almost all of the above-mentioned patents. However, no publication contains any reference to the polymer/polyols according to the invention and the advantages that can be achieved with them.

US-PS 36 55 553 describes that the polyol is preferably a triol, but may contain up to 40% of a diol or tetrol of the same molecular weight range. The molecular weights of the polyols are not more than 5500, are preferably not higher than 5000 and are suitably in the range 1500-5000, preferably 3000-5000.

US-PS 38 23 201 describes the use of a polyol mixture of two polyols with the same molecular weights. DE-OS 25 00 240 describes the preparation of polymer/polyol dispersions from polyol mixtures and vinyl or vinylidene halide monomers and claims improvements in stability. According to the application, it has been found that stable graft copolymer dispersions derived from vinyl monomers can be prepared at temperatures below 100°C and in the absence of auxiliary chain transfer agents when the monomer is vinyl chloride, vinyl bromide, vinylidene chloride or vinylidene bromide. The polymer/polyols prepared from halogenated monomers can interfere with the manufacture of polyurethane products and in many cases are unacceptable for such use because they form acidic decomposition products which interfere with the catalyst.

U.S. Patent No. 3,953,393 describes the preparation of polymer/polyol dispersions by polymerizing vinyl monomers in the presence of alkyl mercaptans as chain transfer agents in specially formulated unsaturated polyols having specific, apparently critical amounts of unsaturated bonds. Such polymer/polyol dispersions have very limited use in the polyurethane field due to the malodor of the polyurethane products made therefrom. This malodor originates from the alkyl mercaptan chain transfer agent which, according to the patent, is necessary for the preparation of the polymer/polyol dispersions and which makes such products unacceptable to the consumer, particularly in the case of mattresses or armrests, impact cushions, etc. The use of alkyl mercaptans required by this patent also entails significant processing problems due to the extremely unpleasant and strong odor of the mercaptans and their harmful effect on those employed in the preparation or use of the dispersions.

The aim of the invention is to produce polymer/polyol preparations that are extremely stable and easy to filter. These preparations should also flow well and be practically free from clumping (nucleation), i.e. show no tendency to settle. The polymer particles of the preparations should be small, and in a preferred embodiment less than 30 microns in diameter. The new polymer/polyol preparations should have exceptionally low viscosities and should also be able to be produced with a relatively high polymer content. The polyurethane products that can be produced from the polymer/polyol preparations according to the invention should have exceptional properties, in particular a high load-bearing capacity (load-bearing capacity) and a high resistance to discoloration.

The present invention achieves the above advantages generally by providing the polymer/polyol preparations defined below which are convertible into polyurethane products, e.g. polyurethane elastomers and high modulus foams, by reaction with polyisocyanates. The addition of a small amount of a higher molecular weight polyol to the lower molecular weight base polyol is essential, as is the ability to operate without halogenated monomers. Alkyl mercaptans or other malodorous and unpleasant materials should not be used.

The invention relates to a polymer/polyol preparation formed by polymerizing one or more ethylenically unsaturated monomers free of chemically bound halogen in a polyol, which is characterized in that it has been prepared by polymerizing the monomer or monomer mixture in the absence of alkyl mercaptan in a mixture of mutually compatible polyols consisting of 55 to 95% by weight of a polyol whose number average molecular weight is not more than 4000 and 45 to 5% by weight of a polyol whose number average molecular weight is not less than 5000, the amount of polymer dispersed in the polyol mixture being 4-40% by weight, based on the weight of the preparation.

The polymer/polyol preparations used are normally liquid, for example at 25°C and preferably at their conversion temperature to a polyurethane product. The polymer/polyols exist as stable dispersions of small particles of the polymer in the polyol. A wide range of free radical catalysts can be used in the polymerization without critically narrow limitations and without affecting stability or filterability. For example, azo as well as peroxide catalysts can be used and safer and easier to use catalysts can be selected than is possible with other processes.

According to a preferred embodiment of the invention, the proportion of the polyol(s) with a number average molecular weight of more than 4000 is between 70 and 90 or 95% by weight, while the proportion of the polyol(s) with a number average molecular weight of not less than 5000 is preferably 5 or 10 to 30 (in this statement and in the corresponding statements above and below, the percentages refer to the total weight of both types of polyols). In another embodiment of the preparation according to the invention, it is prepared using a polyol mixture of 80-90% by weight of a polyol with a number average molecular weight of not more than 4000 and 10-20% by weight of a polyol whose number average molecular weight is not less than 5000.

The above-mentioned polyols with a number average molecular weight not exceeding 4000 are hereinafter referred to as "NM polyols" for short, and those with a number average molecular weight not less than 5000 are referred to as "HM polyols". There is practically no lower limit for the molecular weight of the NM polyol, nor an upper limit for the molecular weight of the HM polyol, as long as the polyols are liquid and the blend and the final polymer/polyol have the desired viscosities. The molecular weight of the NM polyol can be as low as that of dipropylene glycol and is preferably between 400-4000, especially 1000-4000. The molecular weight of the HM polyol is preferably about 5000-20,000, especially 6000-15,000. The respective molecular weights are the critical parameters compared to the respective equivalent weights; e.g. no difference has been found between a diol or triol as HM or NM polyol in achieving the advantages of the invention if the molecular weights are truly the same. In the present case the number average molecular weights of the polyols are used; these are the theoretical values calculated from the theoretical functionality and the hydroxyl number. The true number average molecular weight may be somewhat lower, depending on how much the true functionality is below the starting or theoretical functionality. To obtain stable dispersions, the NM and HM polyols should be compatible with each other.

The polymer content in the polymer/polyol preparations according to the invention is preferably between 15-35 wt.%, based on the total weight of the polymer/polyol preparation.

Any polyol previously used for the preparation of polymer/polyols can be used for the HM and NM polyols according to the invention, provided that it meets the above requirements regarding number average molecular weight and mutual compatibility.

• (a) Alkylenoxid-Addukte von Polyhydroxyalkanen,
• (b) Alkylenoxid-Addukte von nicht-reduzierenden Zuckern und Zuckerderivaten,
• (c) Alkylenoxid-Addukte von Phosphor- und Polyphosphorsäure,
• (d) Alkylenoxid-Addukte von Polyphenolen,
• (e) die Polyole von natürlichen Ölen, wie Rizinusöl.

Suitable polyols for preparing the polymer/polyol preparations according to the invention are the polyhydroxyalkanes, the polyoxyalkylene polyols, etc. The suitable polyols can be selected from one or more of the following classes of preparations alone or in admixture in the usual manner:

• (a) Alkylene oxide adducts of polyhydroxyalkanes,
• (b) Alkylene oxide adducts of non-reducing sugars and sugar derivatives,
• (c) Alkylene oxide adducts of phosphoric and polyphosphoric acid,
• (d) Alkylene oxide adducts of polyphenols,
• (e) the polyols of natural oils, such as castor oil.

Suitable alkylene oxide adducts of polyhydroxyalkanes include, for example, among others, the alkylene oxide adducts of ethylene glycol, propylene glycol, 1,3-dihydroxypropane, 1,3-dihydroxybutane, 1,4-dihydroxybutane, 1,4-, 1,5- and 1,6-dihydroxyhexane, 1,2-, 1,3-, 1,4-, 1,6- and 1,8-dihydroxyoctane, 1,10-dihydroxydecane, glycerin, 1,2,4-trihydroxybutane, 1,2,6-trihydroxyhexane, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane, pentaerythritol, caprolactone, polycaprolactan, xylitol, arabitol, sorbitol and mannitol. A preferred class of alkylene oxide adducts of polyhydroxyalkanes are the ethylene oxide, propylene oxide, butylene oxide adducts of trihydroxyalkanes or mixtures thereof.

Another class of suitable polyols are the alkylene oxide adducts of non-reducing sugars in which the alkylene oxides have 2-4 C atoms. Suitable non-reducing sugars and sugar derivatives are sucrose, alkyl glycosides such as methyl, ethyl glucoside, etc., glycol glycosides such as ethylene glycol glucoside, propylene glycol glucoside, glycerol glucoside and 1,2,6-hexanetriol glucoside, and the alkylene oxide adducts of alkyl glycosides according to US Pat. No. 3,073,788.

Also suitable as polyols are polyphenols, preferably the alkylene oxide adducts thereof in which the alkylene oxides have 2-4 C atoms. Suitable polyphenols are, for example, bisphenol A, p,p'-isopropylidenediphenol, bisphenol F, [(bis(p-hydroxyphenyl)methylene)], condensation products of phenol and formaldehyde, novolak resins, condensation products of various phenolic compounds and acrolein, the simplest member of this class being 1,1,3-tris-(hydroxyphenyl)-propanes, condensation products of various phenolic compounds and glyoxal, glutaraldehyde and other dialdehydes, the simplest members of this class being 1,1,2,2-tetrakis-(hydroxyphenol)-ethanes.

Also suitable as polyols are the alkylene oxide adducts of phosphoric and polyphosphoric acid. Preferred alkylene oxides are ethylene oxide, 1,2-epoxypropane, epoxybutanes, 3-chloro-1,2-epoxypropane, etc. Phosphoric acid, phosphorous acid, polyphosphoric acids such as tripolyphosphoric acid and polymetaphosphoric acids are suitable in this context.

• OH = Hydroxyzahl des Polyols,
• f = Funktionalität, d. h. durchschnittliche Anzahl an Hydroxylgruppen pro Molekül Polyol,
• m.w. = Molekulargewicht des Polyols.

The polyols used can have hydroxyl numbers that vary over a wide range. Typically, the hydroxyl number of the polyols used in the present invention can range from about 20 and below to about 850 and above. The hydroxyl number is defined as the number of mg of potassium hydroxide necessary to completely hydrolyze the fully acetylated derivative prepared from 1 g of polyols. It can also be defined by the following equation: °=c:30&udf54;&udf53;vu10&udf54;OH¤=¤@W:56.1ó1000ó°Kf:mw°k&udf54;¤.&udf53;zl10&udf54;Where

• OH = hydroxy number of the polyol,
• f = functionality, ie average number of hydroxyl groups per molecule of polyol,
• mw = molecular weight of the polyol.

The exact polyol used depends on the end use of the polyurethane product to be manufactured. The molecular weight or hydroxyl number is selected accordingly to obtain flexible or semi-flexible foams or elastomers when the polymer/polyol made from the polyol is converted to a polyurethane. The polyols preferably have a hydroxyl number of 50-150 for semi-flexible foams and from 30-70 for flexible foams. These values are not limiting but are merely illustrative of the large number of possible combinations of the above polyol co-reactants.

The most preferred polyols according to the invention include the poly(oxypropylene) glycols, triols and higher functional polyols; they also include poly(oxypropylene-oxyethylene) polyols. However, it is desirable that the oxyethylene content be less than 80% of the total mass, preferably less than 60%. The ethylene oxide, if used, can be incorporated in any manner along the polymer chain. That is, the ethylene oxide can be incorporated either in internal blocks, as terminal blocks or randomly distributed along the polymer chain. It is known that the most preferred polyols herein contain varying small amounts of unsaturated bonds. According to US-PS 33 04 273, 33 83 351 and GB-PS 10 22 434, the unsaturation itself does not affect in any way the formation of the polymer/polyols of the invention, except in the case where the degree or type of unsaturation is so high or effective that it results in a cross-linked polymer.

The polymerizable ethylenically unsaturated monomers useful in the present invention include materials that are free of bound halogen. Such monomers include the polymerizable ethylenically unsaturated hydrocarbon monomers and polymerizable ethylenically unsaturated organic monomers whose molecules are composed of carbon, hydrogen and at least one of O, S or N. The monomers useful in the present invention are the polymerizable monomers characterized by the presence of at least one polymerizable ethylenically unsaturated group of the type C=C. The monomers can be used individually or in combination to form reactive homopolymer polyol or/mixed polymer/polyol preparations.

These monomers are known and include the hydrocarbon monomers such as butadiene, isoprene, 1,4-pentadiene, 1,6-hexadiene, 1,7-octadiene, styrene, α-methylstyrene, methylstyrene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene and benzylstyrene; substituted styrenes such as cyanostyrene, nitrostyrene, N,N-dimethylaminostyrene, acetoxystyrene, methyl 4-vinylbenzoate, phenoxystyrene, p-vinyldiphenyl sulfide and p-vinylphenylphenyl oxide; the acrylic and substituted acrylic monomers such as acrylic acid, methacrylic acid, methyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, methyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isopropyl methacrylate, octyl methacrylate, methacrylonitrile, ethyl α - ethoxyacrylate, methyl α -acetaminoacrylate, butyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, phenyl methacrylate, N,N-dimethylacrylamide, N,N-dibenzylacrylamide, N-butylacrylamide and methylacrylylformamide; the vinyl esters, vinyl ethers and vinyl ketones, such as vinyl acetate, vinyl alcohol, vinyl butyrate, isopropenyl acetate, vinyl formate, vinyl acrylate, vinyl methacrylate, vinyl methoxyacetate, vinyl benzoate, vinyl toluene, vinyl naphthalene, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether, vinyl 2-ethylhexyl ether, vinyl phenyl ether, vinyl 2-methoxyethyl ether, methoxybutadiene, vinyl 2-butoxyethyl ether, 3,4-dihydro-1,2-pyran, 2-butoxy-2'-vinyloxydiethyl ether, vinyl 2-ethylmercaptoethyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl phenyl ketone, vinyl ethyl sulphide, vinyl ethyl sulphone, N-methyl-N-vinylacetamide, N-vinylpyrrolidone, vinylimidazole, divinyl sulphide, Divinyl sulfoxide, divinyl sulfone, sodium vinyl sulfonate, methyl vinyl sulfonate and N-vinylpyrrole; dimethyl fumarate, dimethyl maleate, maleic acid, crotonic acid, fumaric acid, itaconic acid, monomethyl itaconate, tert-butylaminoethyl methacrylate, dimethylaminoethyl methacrylate, glycidyl acrylate, allyl alcohol, glycol monoesters of itaconic acid and vinyl pyridine. Any of the known polymerizable monomers may be used, the above list being illustrative and not limiting as to the monomers useful in the present invention. Optionally, any known chain transfer agent other than alkyl mercaptans may be present.

The preferred monomer used to produce the polymer of the polymer/polyol preparations according to the invention is acrylonitrile alone as a homopolymer or in combination with styrene as a copolymer. The relative weight ratios of acrylonitrile to styrene are, for example, between 20:80 and 100:0, preferably between 25:75 and 100:0; if low molecular weight polyols, e.g. with a molecular weight below 200, are used, then the weight ratio should in particular be between 60:40 and 85:15. Copolymers of polymerized acrylonitrile, methyl methacrylate and styrene can also be used, the weight ratio being, for example, 25:25:50.

The catalysts suitable for producing the polymer/polyol preparations according to the invention are free radical vinyl polymerization catalysts such as peroxides, persulfates, perborates, percarbonates and azo compounds or all other catalysts specified in the above-mentioned literature references such as 2,2-azo-bis-isobutyronitrile, dibenzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide, diisopropyl peroxide carbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl perpivalate, 2,5-dimethylhexane-2,5-di-per-2-ethylhexoate, tert-butyl perneodecanoate, tert-butyl perbenzoate, tert-butyl percrotonate, tert-butyl perisobutyrate and di-tert-butyl perphthalate. Azobis-(isobutyronitrile) is preferred as a catalyst because it does not impart any unpleasant odor to the product and does not require any special handling in the plant due to potential hazards.

The catalyst concentration is not critical and can be varied within wide limits; for example, it can vary from 0.1-5.0 wt.% based on the total feed to the reactor. Up to a point, increased catalyst concentrations lead to increased monomer conversion, but further increases do not increase conversion significantly. On the other hand, increased catalyst concentration improves product stability. Usually, the catalyst concentration chosen is an optimum value taking all factors into account, including cost.

The polymerization can also be carried out using an inert organic solvent that does not dissolve the polymer. Toluene and benzene are suitable, including the solvents known to be suitable for the polymerization of vinyl monomers. The only requirement regarding the choice of solvent and polyol is that they do not interfere with the polymerization of the monomer. When using an inert organic Solvent is usually removed from the reaction mixture in the usual manner before using the polymer/polyols to produce polyurethane foams.

The temperature range is not critical and may vary from 80°C or less to 150°C or more, preferably 105-135°C. Catalyst and temperature should be selected so that the catalyst has a reasonable decomposition rate relative to residence time in the case of a continuous flow reactor or feed time for a semi-batch reactor.

The preferred process for preparing the polymer/polyol preparations of the invention involves polymerizing the monomers in the polyol while maintaining a low ratio of monomers to polyol throughout the reaction mixture during polymerization. This preferably provides a polymer/polyol preparation in which substantially all of the polymer particles are below 30 microns in diameter, and usually below 1 micron. Such low ratios are achieved by using process conditions which result in rapid conversion of the monomer to polymer. In practice, a low monomer to polyol ratio is maintained in semi-batch and continuous operation by controlling temperature and mixing conditions, and in the case of semi-batch operation also by slowly adding the monomers to the polyol. The process can be carried out in a variety of ways, e.g. by semi-batch reaction in a continuous backmixed stirred tank reactor. For the latter, a second stage can be used to increase the monomer conversion in a batch manner. Mixing conditions such as those achieved by using a backmix reactor (e.g., a stirred flask or autoclave) are used. These reactors keep the reaction mixture relatively homogeneous, thus preventing localized high monomer to polyol ratios that occur in certain stirred reactors.

When using a semi-batch process, feed times (as well as the initial polyol content in the reactor versus the polyol feed with the monomer) can be varied to produce changes in product viscosity. Usually, longer feed times result in higher product viscosities and also allow the use of somewhat wider ranges of acrylonitrile to styrene for a given polyol and polymer content.

The crude polymer/polyol preparations usually contain small amounts of unreacted monomers. These residual monomers can be converted to further polymer by a two-stage operation in which the product from the first stage (the backmix reactor) is passed to a second stage, which may be a conventional reactor or an unstirred tank reactor.

The preferred temperature for preparing the polymer/polyol preparations of the invention is any temperature at which the half-life of the catalyst is not more than 25% of the residence time in the reactor. For example, the half-life of the catalyst at a given reaction temperature may not be longer than 6 minutes (preferably not longer than 1.5-2 minutes). The half-lives of the catalysts become shorter with increasing temperature. For example, azobis-isobutyronitrile has a half-life of 6 minutes at 100°C. The maximum temperature used is not particularly critical, but should be lower than the temperature at which appreciable decomposition of the reactants or products occurs.

In the process used to prepare the polymer/polyols of the invention, the monomers are polymerized in the polyol. Usually, the monomers are soluble in the polyol. It has been found that first dissolving the monomers in a small amount of polyol and adding the solution so formed to the remaining polyol at the reaction temperature facilitates mixing of monomers and polyol and can reduce or eliminate reactor fouling. If the monomers are not soluble in the polyols, known methods (such as dissolving the insoluble monomers in another solvent) can be used to disperse the monomers in the polyol prior to polymerization. The monomer conversion to polymers by this process is remarkably high, e.g. conversions of at least 72-95% of the monomers are usually achieved.

In the interpolymerization of acrylonitrile and styrene, the ratio of acrylonitrile to styrene in the polymer is always somewhat lower than the ratio of acrylonitrile to styrene monomer in the feed because the styrene often reacts somewhat faster than the acrylonitrile. For example, if acrylonitrile and styrene monomers are introduced at a weight ratio of 80:20, the resulting polymer would have an acrylonitrile/styrene weight ratio of about 79:21 or 78:22.

The process of the invention provided extremely stable polymer/polyol preparations which are further characterized by a relatively high polymer content, small polymer particle size, freedom from waste and lumps and their convertibility into highly valuable polyurethane elastomers and foams. In particular, with a given polyol, the present invention allows the ratio of styrene to acrylonitrile or the polymer content to be increased while still obtaining products with improved stability. Furthermore, more stable polymer/polyols are obtained with lower molecular weight polyols than was possible with the known processes. The polymer/polyol preparations of the invention are stable dispersions so that practically all of the polymer particles remain suspended on standing for several months and show no noticeable settling.

The polymer/polyols of the invention comprise dispersions in which the polymer particles (as individual particles or agglomerates thereof) are of relatively small size and, in the preferred embodiment, substantially all below 30 microns. In the preferred embodiment, substantially all of the product, i.e. 99% or more, passes through the filter used in the filtration test of the examples. This enables the polymer/polyol products to be successfully processed in all types of relatively complicated machine systems currently used for large-scale production of polyurethane products, including those which employ impingement mixing which requires the use of filters which cannot tolerate appreciable amounts of relatively large particles. Less stringent claims are made. satisfactory if 50% of the product passes through the filter. For some purposes, products in which only 20% passes through the filter are also suitable. Therefore, the polymer/polyols according to the invention comprise products in which at least 20%, preferably at least 50%, and in particular practically the entire mass, passes through the filter.

The polymer/polyol dispersions of the invention have a higher than normal polymer content in glycols or other very low molecular weight polyols and yet have technically valuable properties such as low waste content, low content of filterable solids and no tendency to settle. The polymer/polyols are normally stable dispersions of insoluble polymers (e.g. acrylonitrile polymers or acrylonitrile/styrene copolymers or polymers of all other monomer systems) in a base polyol. It is known that the molecular weight of the base polyol has a significant effect on the dispersion stability of the polymer/polyol. Usually the higher the molecular weight of the base polyol, the better the dispersion stability. This is why the production of stable polymer/polyols in low molecular weight polyols has been so difficult to date. According to the invention, the addition of a small amount, i.e. 5-45%, of a high molecular weight polyol (mol. wt. 5000 or more) to a low molecular weight polyol results in improved dispersion stability.

The effectiveness of a high molecular weight polyol in improving dispersion stability of a polymer/polyol depends on (1) its molecular weight and (2) its concentration in the polyol blend. The higher the molecular weight, the greater the improvement in dispersion stability achieved by the same amount of addition. The higher the amount of high molecular weight polyol used, the greater the improvement in dispersion stability achieved. A significant improvement in dispersion stability can be achieved by adding as little as 5-45% by weight of a high molecular weight polyol. However, when choosing the amount and type of high molecular weight polyol, other factors such as the effect on expansion and foam properties should also be considered.

The polymer concentration of the polymer/polyol preparations of the invention can be adjusted by adding additional polyol to provide the polymer concentration appropriate for the desired end use. Thus, polymer/polyol preparations can be prepared with polymer concentrations of, for example, 20% and diluted to, for example, 4% by adding more polyol; or the preparation can be prepared directly with a polymer concentration of 4%.

The present invention also relates to the use of the new polymer/polyol preparations for producing new polyurethane products. These polyurethane products are obtained by reacting (a) a polymer/polyol preparation according to the invention, (b) an organic polyisocyanate and (c) a catalyst for reacting (a) and (b) to form the polyurethane product, a blowing agent and a foam stabilizer usually being used in the foam production process. Reaction and foaming can be carried out in any suitable manner, preferably by the one-shot process, although the prepolymer process can also be used if necessary.

The polyurethanes produced can be used successfully for various purposes. For example, the present invention allows the production of polyurethane foams which are conveniently used in the foam board field. Furthermore, the polymer/polyols according to the invention can be used to form polyurethane elastomers in which relatively low molecular weight polyols must be used to provide the required stiffness. Furthermore, the polymer/polyols according to the invention are suitable for the formation of polyurethane products, particularly for purposes where high load-bearing properties are required. The polyurethanes produced are suitable for all purposes in which conventional polyurethanes are used, such as in the manufacture of armrests, impact cushions, mattresses and automobile bumpers.

• A = Acrylnitril; MMA = Methylmethacrylat; S = Styrol
• Poly A = Polyacrylnitril; Poly S = Polystyrol
• A/MMA/S bedeutet das Gewichtsverhältnis von Acrylnitril zu Methylmethacrylat zu Styrol.
• A/S oder A : S bedeutet das Gewichtsverhältnis von Acrylnitril zu Styrol.
• Alle Teile sind Gew.-Teile.

The following terms are used:

• A = Acrylonitrile; MMA = Methyl methacrylate; S = Styrene
• Poly A = polyacrylonitrile; Poly S = polystyrene
• A/MMA/S means the weight ratio of acrylonitrile to methyl methacrylate to styrene.
• A/S or A : S means the weight ratio of acrylonitrile to styrene.
• All parts are by weight.

Residues mean unreacted monomers.

TDI is a mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate.

TMSN is tetramethylsuccinonitrile (a decomposition product of 2,2'-azo-bis-isobutyronitrile.

K1 stands for 2,2'-azo-bis-isobutyronitrile.

TBPO is tert-butyl per-2-ethylhexoate.

All percentages and ratios are weight percent and weight ratios. The examples marked with numbers are according to the invention, the examples marked with letters are comparative examples not according to the invention. The polyols marked with letters are the lower molecular weight polyols, the polyols marked with numbers are those with higher molecular weight.

L.M.W. means lower molecular weight, H.M.W. means higher molecular weight.

Polyol ratios are based on weight and indicate the percentage of low molecular weight polyol first and then the percentage of high molecular weight polyol.

The calculated hydroxyl numbers given in the example tables are based on the calculated total polymer content and the hydroxyl number of the base polyol.

The light transmission data were obtained using light of 500 millimicron wavelength, the polymer/polyol was diluted at 0.01% in a clear solvent.

Polyol I = polypropylene oxide-polyethylene oxide polyol prepared from propylene oxide and ethylene oxide and an 80/20 weight blend of sorbitol and glycerin having a theoretical number average molecular weight of about 10,800 and a hydroxyl number of about 28. The alkylene oxide units were present primarily in blocks and the end units were substantially all ethylene oxide units, i.e., the ethylene oxide was used to terminate the polyol. The polyol contained about 8 weight percent ethylene oxide units based on the total polyol weight.

Polyol II = polypropylene oxide triol made from propylene oxide and glycerin with a theoretical number average molecular weight of about 6000 and a hydroxyl number of about 28.7.

Polyol III = polypropylene oxide-polyethylene oxide triol prepared from propylene and ethylene oxide and glycerin having a theoretical number average molecular weight of about 6000 and a hydroxy number of about 26.1. The alkylene oxide units were present mainly in blocks and the end units were virtually all ethylene oxide units, i.e., the ethylene oxide was used to terminate the triol. Based on its total weight, the triol contained about 14 wt.% C₂H₄O.

Polyol A = tripropylene glycol.

Polyol B = dipropylene glycol.

Polyol C to F = polypropylene oxide diols made from propylene oxide and dipropylene glycol having a theoretical number average molecular weight and hydroxyl number as shown in the following table: °=c:80&udf54;&udf53;vu10&udf54;&udf53;ta10.6:17.6:25.6:28.6&udf54;&udf53;tz.5&udf54;&udf53;tw.4&udf54;&udf53;sg8&udf54;\Polyol\ M.G.\ OH number&udf53;tz5.10&udf54;&udf53;tw.4&udf54;&udf53;sg9&udf54;\C\ Æ400\ 254&udf53;tz&udf54; \D\ Æ700\ 150.5&udf53;tz&udf54; \E\ 1000\ 112.1&udf53;tz&udf54; \F\ 2000\ Æ55.95&udf53;tz10&udf54;&udf53;te&udf54;&udf53;sb37,6&udf54;&udf53;el1,6&udf54;

Polyol G = polypropylene oxide triol made from propylene oxide and glycerin with a theoretical number average molecular weight of about 3000 and a hydroxyl number of about 55.4.

Polyol H = polypropylene oxide-polyethylene oxide triol prepared from propylene oxide, ethylene oxide and glycerin having a theoretical number average molecular weight of about 3000 and a hydroxyl number of 56.4. Substantially all of the ethylene oxide units were internal, i.e. not in the form of end units. Based on its total weight, this polyol contained about 8 wt.% C₂H₄O.

Polyol J = polypropylene oxide-polyethylene oxide triol prepared from propylene oxide, ethylene oxide and glycerin having a theoretical number average molecular weight of about 3600 and a hydroxyl number of about 46.7. Substantially all of the ethylene oxide units were internal, i.e. not in the form of end units. Based on its total weight, the polyol contained about 14 wt.% C₂H₄O.

Polyol K = polypropylene oxide-polyethylene oxide triol prepared from propylene oxide, ethylene oxide and glycerin having a theoretical number average molecular weight of about 2700 and a hydroxyl number of about 62.14. Substantially all of the ethylene oxide units were internal; the polyol contained about 8 wt.% C₂H₄O based on its total weight.

Polyol L = polypropylene oxide-polyethylene oxide triol prepared from propylene oxide, ethylene oxide and glycerin having a theoretical number average molecular weight of about 3400 and a hydroxyl number of about 49. Substantially all of the ethylene oxide units were internal as consecutive blocks; the polyol contained 10 wt.% C₂H₄O based on its total weight.

PP-1 = Dispersion of a 50/50 acrylonitrile/styrene copolymer with 18% copolymer content, prepared in Polyol J using K1 catalyst with a hydroxyl number of 36.9 mg KOH/g.

PP-2 = Dispersion of 72% acrylonitrile and 28% styrene with 27.2% copolymer content, copolymerized in Polyol L using K1 with a hydroxyl number of 36.7 mg KOH/g and a viscosity at 25°C of 2854 cps.

PP-3 = Dispersion of 78% acrylonitrile and 22% styrene with 32.9% copolymer content, copolymerized in Polyol H using TBPO with a hydroxyl number of 37.5 mg KOH/g.

PP-4 = A dispersion of a 55/45 acrylonitrile/styrene copolymer containing 18 wt.% copolymer content prepared in Polyol G using K1 catalyst having a hydroxyl number of 44.3 mg KOH/g.

PP-5 = A dispersion of 78/22 acrylonitrile/styrene copolymer having 29.6 wt.% copolymer content prepared in a triol of propylene oxide, ethylene oxide and glycerin having a theoretical number average molecular weight of about 5,000 and a hydroxyl number of about 34. The alkylene oxide units of the triol were mainly in blocks and the end units were substantially all ethylene oxide units, i.e., the ethylene oxide was used to terminate the triol. Based on its total weight, this triol contained about 14 wt.% C₂H₄O.

tertiary amine catalyst = A mixture of tertiary amines.

Blowing agent I = fluorotrichloromethane.

Amine catalyst = A solution of 70 wt.% bis(2-dimethylaminoethyl) ether and 30 wt.% dipropylene glycol.

Polyol IV = polypropylene oxide polyol prepared from propylene oxide and sorbitol having a theoretical number average molecular weight of about 12,000 and a hydroxyl number of about 27.28.

Polyol V = Polyol, made from 65 wt.% propylene oxide and 35 wt.% ethylene oxide and sorbitol with a theoretical number average molecular weight of about 12,000 and a hydroxyl number of about 27.77. The alkylene oxide units were mainly in blocks and the end units were substantially all ethylene oxide units, that is, 15% by weight of the ethylene oxide was used to terminate the triol. The polyol contained about 44% by weight of ethylene oxide units based on the total product weight.
Silicone surfactant I
MeSi[(OSiMe2 ) _6.4 (OC2 H4 ) _22.3 (OC3 H6 ) _16.4 OC4 H9 ]3 .
Silicone surfactant II

Mixture of 55 wt.% °=c:70&udf54;&udf53;vu10&udf54;&udf53;vz6&udf54;&udf53;vu10&udf54;and 45 wt.% of a mixture of
C₄H�9O(C₂H�4O)₁₈(C₃H�6O) _13.7 H (90 wt%) and
C9 H19 C6 H4 O[C2 H4 O] _10.5 H (10 wt%).

• Eindruckbelastungsverbiegung = ILD ASTM D 1564-69
• bleibende Verformung ASTM D 1564-69
• Zugfestigkeit ASTM D 1564-69
• Dehnung ASTM D 1564-69
• Reißwiderstand (Reißfestigkeit) ASTM D 1564-69

LuftporösitätIn the following examples, the following test procedures were used:

• Indentation load deflection = ILD ASTM D 1564-69
• permanent deformation ASTM D 1564-69
• Tensile strength ASTM D 1564-69
• Elongation ASTM D 1564-69
• Tear resistance (tear strength) ASTM D 1564-69

Air porosity

A foam sample 1.25 cm thick was compressed between two pieces of 6.25 cm inside diameter flanged plastic pipe. This structure then becomes a component in an air flow system. The air enters one end of the pipe at a controlled rate, flows through the foam sample, and exits through a restriction at the rear end of the structure. The pressure drop across the foam due to the restricted air passage is measured with an inclined, closed manometer. One end of the manometer is connected to the upstream side of the foam, the other end is connected to the downstream side. The air flow on the upstream side is adjusted to maintain a differential pressure of 2.54 mm of water across the sample. The air porosity of the foam is expressed as units of air flow per unit area of the sample, namely m³/min/m².

Low density flexible polyurethane foams were prepared from the polymer/polyols of Examples 17 and 24-29 prepared according to the invention and, for comparative purposes, from polymer/polyols not prepared according to the invention. The foam formulations are listed in Tables VIII, X and XI, with amounts given in parts by weight.

The foam formulations were converted to polyurethane foams using the following procedure. The surfactant, polymer/polyol and TDI were weighed into an 8 L stainless steel baffled beaker and mixed for 60 seconds at 2000 rpm using two 6.25 cm 6-blade turbine impellers (spaced 6.25 cm apart at the shaft base). Mixing was stopped for 15 seconds to degas and continued for an additional 5 seconds. Water and amine catalyst mixture were added and mixed for an additional 5 seconds. Stannous octoate was then added and mixed for an additional 5 seconds. The foaming mixture was poured into a 60x60x50 cm paper lined box and the foam rise time was noted. The foam was allowed to cure overnight at room temperature. The physical properties of the foam were measured on a 12 cm sample taken from the bottom of the upper half of the foam pad.

The physical properties of the foams were determined and are listed in Tables IX, X and XI.

Low density, flexible polyurethane foams were prepared from the polymer/polyols of the invention described in Tables XII-XIX and, for comparison purposes, from polymer/polyols not obtained according to the invention. The foam formulations shown in Tables XX-XXVIII were used in the amounts indicated in parts by weight.

The foam formulations were converted to polyurethane foams using the following procedure. The surfactant, polymer/polyol and TDI were weighed into an 8 L stainless steel baffled beaker and mixed for 60 seconds at 2000 rpm with two 6.25 cm 6-blade turbine impellers (spaced 6.25 cm apart at the base of the shaft). Stirring was stopped for 15 seconds to degas and continued for an additional 5 seconds. Water and the amine catalyst mixture were added and mixing continued for another 5 seconds. Stannous octoate was then added and mixed for another 5 seconds. The foaming mixture was poured into a 60x60 50 cm paper-lined box and the foam rise time was noted. The foam was allowed to cure overnight at room temperature. Its physical properties were measured on a 15 cm sample taken from the bottom of the top half of the foam pad.

The physical properties of the foams were determined and are given in Tables XXI-XXVIII using the following test procedures:
Creaming time

Time interval from the formation of the complete foam formulation to the appearance of a creamy color in it. The creaming time is proportional to the reaction speed of the formulation.
Ascent time

Time interval from the formation of the complete foam formulation to the achievement of the maximum foam height.
Breathability = ASTM D-1564-69.
Reflectance or color eye reflectance

Using a standard color eye model (No. D1), a numerical rating from 0 to 100 was made on test samples by comparison with a series of standard samples. A rating of "100" corresponds to a sample rated as white.
Normalized ILD values

For comparison purposes, the ILD values measured at the actual foam thickness were converted to "normalized" ILD values of a second density by linear ratio, i.e., the normalized ILD value is calculated by multiplying the measured ILD value by the second density and dividing by the actual density.
Load ratio

Ratio of the ILD value at 65% bending to the ILD value at 25% bending.
Silicone surfactant III

Mixture of non-hydrolysable silicone-oxyalkylene block copolymers consisting of blocks of dimethylsiloxy units and blocks of propylene oxide and ethylene oxide units.
Filterability

The preferred preparations of the invention are substantially free of polymer particles having a diameter greater than 30 microns. A preparation meets this criterion if more than 99% by weight of the preparation passes through a sieve 1 and a sieve 2 in succession in the following test. A 470 g sample of the test preparation is diluted with 940 g of anhydrous isopropanol to reduce the viscosity effect and the diluted sample is passed through a 15.5 cm² square sieve 1 and then through a sieve 2 of the same size. (The sieves are cleaned, dried and weighed before the test.) They are then washed with isopropanol to remove any polyol, dried and weighed. The difference between the final and initial sieve weights corresponds to the amount of polymer not passing through the sieves. Sieve 1 has square meshes with an average mesh opening of 105 microns and sieve 2 is made of cloth with average openings of 30 microns.
Centrifugable solids

The polymer/polyol preparation is centrifuged at about 43,000 rpm and 1470 g for about 24 hours. The centrifuge tube is then inverted and allowed to drain for 4 hours. The non-flowing cake remaining at the bottom of the tube is reported as a weight percent of the original weight of the test preparation.
Clear layer before emptying

The polymer/polyol preparation is placed in a small test tube and centrifuged for approximately 24 hours. After this, the liquid in the test tube is observed and the height of the upper clear layer is measured. This height is expressed as a percentage of the liquid height in the test tube.

Example 1 to 37 and A to F

Examples 1-37 and AF were run continuously in a 550 cc stirred tank reactor equipped with baffles and a stirrer operating at 800 rpm. The feed components were continuously pumped into the reactor after passing through an on-line mixer to ensure complete mixing of the feed components prior to entering the reactor. The internal reactor temperature was controlled to 1°C by externally heating or cooling the reactor. The product from the reactor flowed out through a back pressure regulator (set to give a back pressure of 0.7 atm in the reactor). The product then flowed through a water cooled tubular heat exchanger to a receiving vessel. Portions of the crude product were vacuum at 2 mm pressure and 120-130°C for testing. Conversions were determined from gas chromatographic analysis of the amount of unreacted monomers present in the crude product prior to distillation.

The experimental conditions and results of the above examples are shown in the following Tables I-VII. Table I &udf53;vu10&udf54;&udf53;vz54&udf54;&udf53;vu10&udf54;

Acrylonitrile and styrene in a weight ratio of 78/22 were added with K1 to an 80/20 weight mixture of 1,4-butanediol and polyol I. In the feed, the K1 concentration was 0.5 wt.% and the monomer plus K1 content was 20.07 wt.%. The feed rate of the polyol mixture was 2270 g/h, that of the monomer and K1 feed was 570 g/h. The product was obtained at a rate of 2836 g/h, the material balance (quotient of product weight and total feed of polyol, monomer and 2,2'-azo-bis-isobutyronitrile. This value is theoretically 100%, but in practice it is higher or lower, e.g. due to losses, impurities) was 99.86%. However, this product settled in layers overnight, which shows the effect of the incompatibility of the polyols. &udf53;ns&udf54;¸&udf50;&udf53;ns&udf54;&udf53;ns&udf54;¸&udf50;&udf53;ns&udf54;&udf53;vz21&udf54;

Example 27 to 30

In these examples, a polyol blend of 85 wt.% Polyol K and 15 wt.% Polyol III was used. The reaction temperature was 125°C and the residence time was 12 minutes. The remaining conditions and procedures are set forth in Table V below and the general process conditions are described in the examples above. Table V &udf53;vu10&udf54;&udf53;vz47&udf54;&udf53;vu10&udf54; Table VI ¸&udf50; Table VII &udf53;vu10&udf54;&udf53;vz57&udf54;&udf53;vu10&udf54;

Example 30 to 48

In these examples, the polymer/polyols prepared in Examples 17 and 24 through 29 were compared with other polymer/polyols identified by "PP" and a number. Table VIII &udf53;vu10&udf54;&udf53;vz31&udf54;&udf53;vu10&udf54; Table IX &udf53;vu10&udf54;&udf53;vz26&udf54;&udf53;vu10&udf54; Table X &udf53;vu10&udf54;&udf53;vz46&udf54;&udf53;vu10&udf54; Table XI &udf53;vu10&udf54;&udf53;vz50&udf54;&udf53;vu10&udf54;

The data in Table X demonstrate that the polymer/polyols of the present invention can be used to produce flexible foams with higher load-bearing properties for use as carpet underlay or rigid polyurethane elastomers with higher modulus for use in the automotive industry. Furthermore, the flexible foams produced from polymer/polyols with lower acrylonitrile to styrene ratios are relatively non-staining while having higher load-bearing capacity as shown by the data in Tables VIII and IX. It would be expected that the addition of 15% of a high molecular weight polyol in the foam formulation would reduce the load-bearing properties of the foam by perhaps 10%. In contrast, the foam evaluation data in Tables VIII, IX and X demonstrate that, unexpectedly, there is no loss of foam load-bearing properties.

Example 49 to 93 and L to O

Examples 49-93 and LO were run continuously in a continuous stirred tank reactor equipped with baffles and a stirrer typically operated at 800 rpm. The feed components were pumped in for continuous reaction after passing through an intermediate mixer to ensure complete mixing of the feed components prior to entering the reactor. The internal reaction temperature was controlled to 1°C by applying controlled heating or cooling to the outside of the reactor. The product from the reactor flowed out through a back pressure regulator (set to give a back pressure of 0.7 atm in the reactor). The product then flowed through a water cooled tubular heat exchanger to the product receiving vessel. Portions of the crude product were vacuum stripped at 2 mm pressure and 120-130°C for testing. Conversions were determined from gas chromatographic analysis of the amount of unreacted monomers present in the crude product prior to stripping.

The experimental conditions and results of these examples are shown in Tables XII to XIX below. The polyols used were identified above. Table XII Table XIII Table Table XVII Table XVIII Table XIX &udf53;vz67&udf54;

Example 94 to 127 and P-II

In these examples, the polymer/polyols of the invention were compared with other polymer/polyols designated by "PP" and a number in the production of foams. &udf53;ns&udf54;¸&udf50;&udf53;ns&udf54;&udf53;ns&udf54;¸&udf50;&udf53;ns&udf54;¸&udf50;&udf53;ns&udf54;&udf53;ns&udf54;¸&udf50; Table XXIII Table XXIV Table XXV Table XXVI Table XXVII &udf53;vu10&udf54;&udf53;vz32&udf54; Table XXVIII &udf53;vu10&udf54;&udf53;vz30&udf54;

Claims (9)

1. Polymer/polyol preparation formed by polymerizing one or more ethylenically unsaturated monomers free of chemically bound halogen in a polyol, characterized in that it has been prepared by polymerizing the monomer or monomer mixture in the absence of alkyl mercaptan in a mixture of mutually compatible polyols consisting of 55 to 95% by weight of a polyol whose number average molecular weight is not more than 4000 and 45 to 5% by weight of a polyol whose number average molecular weight is not less than 5000, the amount of polymer dispersed in the polyol mixture being 4-40% by weight, based on the weight of the preparation. 2. Preparation according to claim 1, characterized in that it has been prepared using a polyol mixture of 70-90% by weight of a polyol whose number average molecular weight is not more than 4000 and 10-30% by weight of a polyol whose number average molecular weight is not less than 5000. 3. Preparation according to claim 1 to 2, characterized in that the polymer contains polymerized acrylonitrile and also polymerized styrene in a weight ratio of acrylonitrile to styrene in the polymer between 20:80 to 100:0. 4. Preparation according to claim 1 to 2, characterized in that the polymer contains polymerized acrylonitrile and also polymerized styrene in a weight ratio of acrylonitrile to styrene in the polymer between 40:60 to 85:15. 5. Preparation according to claims 1 to 4, characterized in that the number average molecular weight of the low molecular weight polyol is in the range of 400-4000 and that of the higher molecular weight polyol is between 5000-20 000. 6. Process for the preparation of the polymer/polyol preparation according to claim 1, characterized in that the monomer or monomer mixture is polymerized in the presence of a free radical catalyst in the absence of alkyl mercaptan in a polyol mixture of 55-95% by weight of a polyol with a number average molecular weight not exceeding 4000 and 45-5% by weight of a polyol with a number average molecular weight not less than 5000. 7. Process according to claim 6, characterized in that a polyol mixture is used which consists of 70-95% by weight of a polyol with a number average molecular weight not exceeding 4000 and 5-30% by weight of a polyol with a number average molecular weight not less than 5000. 8. Use of the polymer/polyol preparation according to claim 1 for the production of optionally foamed polyurethanes in a manner known per se. 9. Use of the polymer/polyol preparation according to claim 1 based on an alkylene oxide adduct of a polyhydroxyalkane and water as a blowing agent for producing flexible foams with a density below 0.028 g/cm³ by the one-shot process in a manner known per se.